Putting all the McClellan stuff in one place...

Saphroneth

Major
Joined
Feb 18, 2017
Strengths at the opening of the campaign


The question of strengths in the Maryland Campaign is an extremely contentious topic, but it should really be considered to be divided into several separate questions because "how strong is X unit" has multiple possible answers.


For the Union, we are fortunate enough to have their PFD strength according to September 20 returns properly filled out. There is however no September 10 return for the full army (though there are some September 10 returns for parts of the Washington defences) and this should be kept in mind; in particular, some units joined McClellan after he marched out of Washington itself. The September 20 returns may also reflect a somewhat diminished state for some units.


For the Confederates, things are considerably more confusing.


The possible answers for the question "how strong is X unit" could have these sorts of answers:
"The unit is formed of 256 companies, meaning 25.6 full regiments of all arms".
"The unit has 21,000 men aggregate present and absent, meaning there are 21,000 men on the rolls associated with this unit who have not been struck off through death or discharge."
"The unit has 15,000 men Aggregate Present".
"The unit is a moving body of 17,000 men including non soldiers" (a situation chiefly found with the Confederates who used slaves and free blacks in their logistics train)
"The unit has 12,000 men in Union regulation PFD."
"The unit has 9,500 men who would normally be expected to form line of battle" ("effectives", which is Confederate PFD)
"The unit has currently got 7,500 men in line, after straggling and/or casualties"

Straggling can best be defined as men who are not with their unit when they should be, but who have not actually deserted - just been unable to keep up, or "wandered off" for a bit, mostly. It's attributable to the relatively incomplete discipline of the American volunteer armies, at least in extent.


What we do know is that, as of September 2nd, the effective strength of the Confederate army (about two thirds of which had just fought in Second Bull Run) was around 75,000, composed of the divisions of Jackson, Ewell, AP Hill, DR Jones, Wilcox, Hood/Evans*, Anderson, McLaws, DH Hill and Walker (of varying sizes, with Walker's division consisting of two brigades and AP Hill's divsion consisting of six) plus three sizeable brigades of cavalry under Stuart. This would equate to around 94,500 men PFD by Union measures (or another way to put it is that a force of 94,500 PFD Union troops would be expected to put about 75,000 effective men into battle under broadly normal conditions). This force could be reduced significantly by hard marching and periods of time without food, as well as by the disruptive effect of battle.

* this designation used because there was effectively an ongoing leadership dispute

Another way to put it is that the force with which Lee marched to invade Maryland consisted of approximately 2015 companies (of which 76 were artillery batteries and 124 were cavalry companies).


I should pause here to address the idea that the force post-Second-Bull-Run was much smaller than this.
The idea that it was around 50,000 (though in what category is not usually described) has come up in the past in various sources, such as Stephen W. Sears' books, but the logic involved does not hang together. Just as one example, the force which Lee had on October 10 after all the fighting of the campaign was 64,000 Confederate PFD, and given known casualties in the Maryland Campaign this would imply that there were around 75,000-80,000 in that category before the start of the campaign (depending on how many wounded had recovered by October 10). It's not really believable that the exceptionally bloody Battle of Antietam could cause an army to gain tens of thousands of men without the addition of new formed units!


There are multiple strands of evidence to support the idea that Lee's army in the Maryland Campaign was large - not necessarily larger than McClellan's, but not out of the same size class. In addition to the post-Second-Bull-Run state (which is before crossing the Potomac) there's also the post-campaign situation with add-back of casualties, the regiment counts (which are comparable for both sides), reports by individual commanders actually at Antietam (in Carman, which - with further analysis - will be addressed later) and the eyewitness reports of the moving Confederate army. While these do not agree exactly, they all line up with one another to the extent that we can be fairly confident about this statement:


When McClellan left Washington, he was facing an army of about the same size as his own force at that time.
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
...
Pope's replacement]
...

Regarding Pope’s replacement, I once read a newspaper “gossip” report from September 1862 that Lincoln had gone to the most senior corps commanders (Banks, Sumner, Burnside - not just most senior, but unlike Franklin and Porter, not thought of as in the McClellan clique) to see who should replace Pope, as if he was fishing for some choice other than McClellan — each of those three told him that McClellan was the only choice they wanted. Unfortunately I can’t find the article again.
 

Saphroneth

Major
Joined
Feb 18, 2017
The composition of McClellan's army on marching out of Washington


While McClellan made a few movements before the opening of the Maryland Campaign proper (by moving Sumner's wing out to Rockville, on the most direct road from Washington to Frederick), the campaign proper effectively began on the 8th, which is the second full day after McClellan gaining command of the field army.


The force consisted of:


Sumner's Wing

2nd Corps - two divisions.
Richardson:
On marching out 13 regiments and 2 batteries
Gains 1 new regiment after Antietam (145 PA)
Sedgwick:
On marching out 13 regiments and 3 batteries
No change during campaign

In addition, French's division was created on 10th September from troops who had joined en route. It consisted of four regiments of Kimball's brigade (old regiments), four new regiments from Washington (132 PA, 14 CT, 108 NY, 130 PA), three old regiments from the Dept. of SC, and the two batteries of the 2nd Corps artillery reserve. It did not march out with McClellan, but was complete (as 11 regiments and 2 batteries) by Antietam.

Corps marches out with 26 regiments and 7 batteries.


12th Corps (for simplicity I will use this term) - two divisions.
Williams:
On marching out 8 older regiments, 4 new regiments (124 PA, 125 PA, 13 NJ, 107 NY), 3 batteries
Gains 1 new regiment en route (128 PA)
Gains 1 new regiment after Antietam (20 CT)
Greene:
13 regiments and 3 batteries.
Corps marches out with 25 regiments and 5 batteries.
Wing marches out with 51 regiments and 13 batteries.

Burnside's wing.

9th Corps - four (small) divisions

Wilcox:
On marching out 7 older regiments, 1 new regiment (17 MI) and 2 batteries
1 older regiment joined en route (45 PA)
Gains 1 new regiment after Antietam (20 MI)
Sturgis:
On marching out 6 older regiments, 1 new regiments (35 MA), 2 batteries
Gains 1 new regiment en route (9 NH)
Rodman:
On marching out 6 older regiments, 1 new regiment (16 CT), 1 battery
Gains 1 new regiment after Antietam (21 CT)
Cox/Scammon (Kanawha):
6 regiments, 2 batteries, and 4 companies cavalry
Corps marches out with 28 regiments, 7 batteries, 4 companies cavalry

1st Corps (again, redesignated as such during the camapign) - three divisions.
King/Hatch/Doubleday:
17 regiments and 4 batteries.
Ricketts:
On marching out 12 older regiments, plus 1 new regiment (16 ME), which missed Antietam (it was detached as a guard) and 4 batteries.

Meade:
13 regiments and 4 batteries.
Corps marches out with 43 regiments and 12 batteries
Wing marches out with 71 regiments, 19 batteries, 4 companies cavalry

Franklin's Wing

6th Corps
Slocum's division:
12 regiments and 4 batteries, with no change in the timeframe of the fighting.
Smith's division:
Marched out with 14 old regiments, 1 new regiment (137th PA) and 5 batteries. (one of these batteries went to Couch, not listed there)
The 21st NJ joined just after the battle.

Corps marches out with 25 regiments and 9 batteries.

4th Corps
Couch's division:
Marched out with 13 old regiments, 2 new regiments and 3 batteries

Wing marches out with 40 regiments and 12 batteries.


5th Corps
Sykes' division was the only one which marched out with McClellan. It contained 2 proper regiments and battalions from 9 regular infantry regiments, plus 4 batteries of artillery.

Morell's division joined the army after South Mountain, and consisted of 17 old regiments, 2 new regiments (20th ME, 118th PA) and 4 batteries.

Humphreys' division joined the army after the fighting at Antietam, and consisted of one old regiment, seven new regiments and 2 batteries.


In total, in infantry organizations, McClellan marched out with 173 infantry regiments and 48 batteries (plus some batteries with the artillery reserve, which are a little harder to track as the reserve was being broken up to replace guns lost at Second Bull Run)

McClellan also brought with him a number of cavalry regiments, though the organization is complicated and shifted around day-to-day as mission detachments were made. All told the cavalry amounts to perhaps a dozen regiments, not all of which was at Antietam itself.
The primary cause of the chaos in the cavalry is just that there was only one brigadier available, that being Pleasonton:
McClellan's cavalry commander was Stoneman, but his problem with piles made commanding a cavalry unit extremely painful. He was thus shifted into the infantry, and McClellan assigned Buford and Bayard as division commanders for his field cavalry and Washington defences cavalry respectively. However, Buford was injured (broken knee, it seems) and could not always command actively, while Averell (one of the two brigadiers for the field) and Gregg (McClellan's other choice for a brigadier) were both wounded as well; this basically left Pleasonton as the senior field commander as the last healthy man.

Despite this organizational complexity, the cavalry in the Maryland Campaign actually performs well given their strength, and it's hard to argue with that.



To get at the strength of McClellan's army when he actually left Washington, we need to look at his list of strengths in the battle and evaluate carefully.


His listing of strengths at Antietam gives, in PFD:

1st Corps 14,856
2nd Corps 18,813
5th Corps (one division not arrived) 12,930
6th Corps 12,300
9th Corps 13,819
12th Corps 10,126
Cavalry Division 4,320 - this is not all of the cavalry as some was detached,


This is clearly based on the 20 September report with casualties added back for Antietam and only Antietam. Thus to get the strength McClellan marched out with, we can take these strengths and add back the casualties suffered at South Mountain, and then attempt to deduct the strengths of the units which joined later.

Doing the first step we have:

1st Corps 15,789
2nd Corps 18,813
Couch 7,219
5th Corps (Sykes and Morell only) 12,930
6th Corps 12,833
9th Corps 14,677
12th Corps 10,126
Cavalry Division 4,321

We also know Humphreys' division was about 6,800, and was almost entirely new regiments. Based on this the PFD strength of a brand new regiment is about 850 PFD as a working figure.

1st Corps has one unit which missed Antietam itself, the 16th Maine, but this unit marched out with the corps. No adjustment required, so 15,789 PFD marched out

2nd Corps gained the 145th PA after Antietam but by 20th September, and in addition French's entire division did not march out with the rest of the corps. With 39 regiments (5 new) carried on the return of which 13 (all 5 new) did not march out, I estimate:
18,813
- 4,250 (five new regiments)
= 14,563 (34 old regiments of which 26 marched out, plus 7 batteries which all marched out)
x 267/347 (companies pro rata)
= 11,205 PFD marched out

4th Corps (Couch)
No adjustment necessary. 7,219 PFD marched out

5th Corps (Sykes)
Estimating Sykes is a bit difficult as his division isn't a "conventional" division, but estimating it at 1/3 of the total strength of 5th Corps at Antietam seems like a reasonable first assumption. This would give 4,310 PFD marched out

6th Corps needs to have the 21st NJ deducted, which would be 850 PFD per the estimate derived from Humphreys and would leave 11,933 PFD marched out.

9th Corps gained two regiments en route (45 PA, an old regiment, and 20 MI, a new one). The other regiments which joined after Antietam had not joined by the 20th and as such would not be on the 20th September return.
This implies:
14,677
- 3400 (the four new regiments)
= 11,277 (the 26 old regiments, 7 batteries, 4 companies art)
11277/271 = 41.6 average PFD per old company

So 14,677 - 850 (20 MI) - 416 (45 PA) = 13,411 PFD marched out


12th Corps has a peculiarity, because three regiments from this corps were dropped off at Frederick to guard the depot. These totalled 1,110 PFD on 20 September and were carried on a separate row on the report, so we need to add those.
We also need to deduct the 128th PA. The 20th CT arrived after the 20th so we don't need to deduct it.
So 10,126 + 1,110 - 850 = 10,386 PFD marched out

Total in infantry organizations: 74,523 PFD marched out

The cavalry adds about another 6,000 to 7,000, and given that this is an estimate I think we can say that the force that marched out of Washington was about 82,000 PFD all told. It would gain reinforcements throughout the campaign, though to a first approximation these consisted of French's division (joined before South Mountain), Morell's division (joined between South Mountain and Antietam) and Humphreys' division (joined after Antietam).


Effectively this means that we can think of the two commanders as having about the same number of troops for the campaign, though McClellan gained reinforcements over the course of it (and the troops at Harpers Ferry were also Union troops, though explicitly not part of McClellan's army per the decision of Halleck). We should note however that a significant part of McClellan's force was composed of new regiments, which are not as effective man for man as ones with longer training (though they would be perhaps as effective as the same number of regiments of experienced troops).
 

Saphroneth

Major
Joined
Feb 18, 2017
Regarding Pope’s replacement, I once read a newspaper “gossip” report from September 1862 that Lincoln had gone to the most senior corps commanders (Banks, Sumner, Burnside - not just most senior, but unlike Franklin and Porter, not thought of as in the McClellan clique) to see who should replace Pope, as if he was fishing for some choice other than McClellan — each of those three told him that McClellan was the only choice they wanted. Unfortunately I can’t find the article again.
Franklin is an interesting one because McClellan doesn't seem to have thought that highly of him - certainly not after the disappointment at Glendale - but he still stepped in to protect him. Of course it could just be the question of who the alternatives were.

I think there's also a definite merit to the idea that Lincoln had his own ideas about what he wanted done a lot of the time and was basically "searching for justification" - he often didn't think the ideas were necessarily good enough to implement them himself (overriding the actual commanders) and take the fall if he was wrong, but he was willing to try asking over and over again until he got the answer he wanted...
 

Saphroneth

Major
Joined
Feb 18, 2017
For the purposes of this look at the Maryland Campaign I'm going to be using the maps from the GCACW series, by Multi-Man Publishing. They're good at showing the roads and show most if not all of the fords, and so it's a little easier to keep track of the options.


First, here's a look at the situation as of the night McClellan recieved command.


Night_of_6th.jpg

Red: Confederate infantry. Orange: Confederate cavalry. Green: Union cavalry. Blue: Union infantry.

This map is less complete than later ones. I haven't marked the Washington defences (which included Morell of 5th Corps, all of 3rd and 11th Corps, units which would later be attached to 2nd and 5th Corps, and a sizeable garrison besides), but the Union forces which would march out a day or two later are already positioned for defence.


So let's look at this from Lee's point of view first. At this point he's captured Frederick, which is a fairly noteworthy achievement given that it amounts to an actual invasion of a non-seceded state, but he now has to consider where to go from here; it is for example fairly obvious at this point that the people of Western Maryland at least are not seeing his army as liberators in the main.
One thing he could do is to just sit here at Frederick and court a battle, but that has possible supply line problems (which McClellan may or may not have known about), or he could move in one of a number of directions - towards Baltimore, north into Pennsylvania, west to Harpers Ferry, or directly after Washington (on either side of the Potomac).
His scouting cavalry is running into the Union screen, so he doesn't have good information on Union positions, but he can estimate depending on when he thinks the Union will leave Washington.

This means McClellan has to allow for those options. He also has something else to consider, which is the question - is there another Confederate column coming up from Richmond?
This was a real risk at the time, but it's something that McClellan appears to have considered (but not let himself get too focused on). Halleck appears to have been more worried about it than McClellan was, and even with all the reinforcements sent to McClellan there was still a force of around 70,000 PFD in Washington on the 20th.


Of the possible directions Lee could be going, the one which has the greatest risk which McClellan can alleviate by his movements is to go after Baltimore. Taking Baltimore would be a massive propoganda victory for the Confederates, while the Washington defences are less capable to the east, and cutting Washington off from supply would offer at least the possibility of a "far siege". Meanwhile for McClellan to simply send his forward forces (Sumner) moving against Frederick in the shortest possible time would mean letting Lee concentrate all of his combat power against Sumner's wing, which would be a bad thing to have happen.
McClellan thus has to balance:
- Protecting Baltimore.
- Keeping between Lee and Washington as much as practical.
- Getting his troops into a position where they are mutually supporting down multiple approach roads.

It's worth thinking at this point about what McClellan's options could be, and how Lee could react to them. McClellan can hope to disguise his movements thanks to his cavalry screen, but that's not something he can rely on - and Lee might guess right, anyway.



I should also note as an aside that McClellan ends up advancing on the 8th, because it's worth pointing out. The "stereotypical timid McClellan" might not have advanced at all, but between getting the command and moving out with the field army is less than two days.
 
Joined
Dec 22, 2016
Location
NH
If Lee moved to Baltimore, his flank was exposed to the advancing Federals. The moon and Baltimore were about as equally endangered by the Confederates in September 1862. Carman, who walked and fought in the campaign, said the Army of the Potomac should've been at Frederick on the 10th of September. Jacob Cox, a friend of McClellan and general in the 9th Corps, wrote the army should've moved faster as well. Ethan Rafuse, who wrote an excellent defense of McClellan's generalship in the 21st Century, admitted McC failed to support Pope sufficiently. He agreed with Lincoln's "he has acted badly" regarding McC's actions on that question. Are you approaching hagiography in your attempts to vindicate McClellan? I'm not saying you are, but could McClellan do wrong in your eyes? You sure spared no condemnation of Burnside in your recent posts about Fredericksburg.
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Cox was a "friend of McClellan's"? Is that the same Cox who wrote a complete hatchet-job on McClellan to cover up for Cox's own failings in West Virginia and Maryland?

Carman said McClellan should have been in Frederick on the 10th? Can I have a page number, because I find he writes:

"McClellan reported up to this time his movements were for the purpose of feeling the enemy, “to compel him to develop his intentions, at the same time the troops were in position ready to cover Baltimore or Washington, to attack him should he hold the line of the Monocacy, or to follow him into Pennsylvania if necessary.”39 Cautious and deliberate as was McClellan’s advance there were reasons for it, beyond Halleck’s warnings, in the condition of the transportation and artillery, the vigilance and superb handling of the Confederate cavalry and consequent ignorance of the Confederate movements. The Quarter Masters [sic] Department was sadly disorganized. The trains of the Army of the Potomac, brought from the Peninsula, were not promptly disembarked, and when disembarked were not properly distributed to the divisions to which they belonged. The Army of Virginia had lost much of its transportation...

Rumors of the most conflicting character came to him hourly, upon which he and his lieutenants built theories of the most plausible and irreconcilable kind. While a movement on Baltimore was considered entirely too hazardous, it was nevertheless borne in mind that Lee and his able lieutenants were prone to make hazardous movements with great success. Lee’s masterly movements in front of Richmond by which McClellan had been driven to the James River were keenly remembered and Jackson’s movement upon Manassas, in defiance of all ordinary rules of strategy, was not forgotten."

Carman, General Ezra A; Clemens, Thomas G.. Maryland Campaign of September 1862: Volume 1, South Mountain . Casemate Publishers. Kindle Edition.

You do know that by far the most complete analysis of the situation of the reinforcements to Pope was Carman, and on reading the recorded communications, he completely changed his find and found McClellan was correct (as famously did Emory Upton).
 

Saphroneth

Major
Joined
Feb 18, 2017
If Lee moved to Baltimore, his flank was exposed to the advancing Federals. The moon and Baltimore were about as equally endangered by the Confederates in September 1862. Carman, who walked and fought in the campaign, said the Army of the Potomac should've been at Frederick on the 10th of September. Jacob Cox, a friend of McClellan and general in the 9th Corps, wrote the army should've moved faster as well. Ethan Rafuse, who wrote an excellent defense of McClellan's generalship in the 21st Century, admitted McC failed to support Pope sufficiently. He agreed with Lincoln's "he has acted badly" regarding McC's actions on that question. Are you approaching hagiography in your attempts to vindicate McClellan? I'm not saying you are, but could McClellan do wrong in your eyes? You sure spared no condemnation of Burnside in your recent posts about Fredericksburg.
I certainly think McClellan could do wrong; I think his flaws however are mainly political.

Firstly in that he wasn't very good at politics, and disdained it enough that he didn't realize it was impossible to avoid at his rank; secondly in that he either didn't realize that his interactions with some people were political or didn't think through/care about how it looked. His interactions with Lincoln also have some of this in them, in that McClellan often fails to see the extent to which he needs to address not merely the military case for doing something but also the political case, and he has no real counter to the political manoeuvering of others back in Washington.

Similarly he's unable to effectively navigate the inter-service politics which leads to the lack of a Yorktown bombardment.

There are also errors in other cases, but they tend to be more minor. It's I think telling that in a lot of cases the problems come up wherever McClellan is not.


I tend to the view that the first thing we should ask is why a commander did what they did; second we should ask what their alternatives were.



In this post you've raised these issues:

- The danger to Baltimore being overblown

- Getting to Frederick

- Supporting Pope.

I'll take those in order, if I may.


As to the first question about the danger to Baltimore, we should consider firstly why the danger to Baltimore would be overblown. There's nothing actually physically in the way that would prevent Lee from marching to Baltimore except distance, and he has two pike roads to use to do it with - one of those being the direct route along the National Road (a little under 50 miles) and the other being the road via Westminster (about 60 miles).
If Lee marches the majority of his army along these roads, then he is vulnerable to interception, but he's vulnerable to interception precisely because the Union can move troops north (which is what McClellan actually does). If for example McClellan doesn't start moving troops to the National Road until he's certain that the Confederates are making that movement, he wouldn't be finding out about it until their infantry was around Parrsville - by which point the Confederates would be 33 miles from Baltimore (less, due to the travel time of information) and all points on the Rockville-Frederick pike road are at least five miles further than that from Baltimore.
In other words, if McClellan waits until he's sure Lee is actually doing it, he's too late to respond with his field army.

Of course, sending troops north to the National Road (which is what McClellan actually does when he marches out) not only helps cover the National Road (first reducing the response time, then blocking it, and also making the Westminster route much riskier as it would divide the Confederate army if they took that route) but it also enables the move on Frederick as it allows for a second main axis of advance.


Which is what relates to the second question, about getting to Frederick.

McClellan's force marches out on the 8th, with their leading edge at Rockville on the night of the 7th. For that leading edge to reach Frederick by the night of the 10th (three days of marching) would take three days of marching at ten miles per day, which is achievable (if difficult, given the mixed state of the army) but it would just be the leading edge with the rest of the force stacked up behind them, coming in along a single road; that McClellan was doing this would become obvious to Lee by the night of the 9th or the morning of the 10th, and Lee's forces were mostly camped east of Frederick until the 10th historically (most of the force marched through the streets of Frederick on the 10th) which means that Lee would be able to respond quickly and bring most of his army to bear on the leading edge of McClellan's army.
Simply to close up and bring the rest of the Union army into play would add a fourth day at least, which brings the arrival date to the end of the 11th.

The only way it makes sense to plunge ahead at maximum speed to get the leading edge to Frederick as soon as possible is if you know that Lee is moving west, and if Lee is not allowed to change his plans when he sees what you're doing.




As for the third point, about getting troops to Pope, the question is simple - what more could McClellan have done that was within his authority?
When evacuating the sick, McClellan was as quick as his logistical situation allowed, and he sent off the sick in keeping with the timeframe he had informed Halleck of in advance (and was able to largely make up the time lost when Halleck had him send cavalry and artillery to Burnside); when he was loading up his forces from the Fort Monroe area, he got off as many troops in one go as he had transports for in only a day or two. That's quick work.

He doesn't turn up at Alexandria until after 3rd and 5th Corps have joined Halleck, and after AP Hill at Bull Run Bridge and Centreville has enveloped Pope; at that point the choices are either sending unsupported infantry marching off without supplies into an unknown but strong Confederate force (and thus not getting them to Pope anyway, as far as he could possibly know) or spending the time to get the troops properly sorted out for an advance to contact, and McClellan goes beyond what anyone else of comparable rank does in trying to get troops to Pope. If he'd had the wagons and cavalry earlier then 6th Corps could have marched out earlier (or at least five brigades of them, the ones Halleck hadn't ordered into the Washington defences), but that's up to Halleck not McClellan.

So, what more could McClellan have done that was within his authority?
 

Saphroneth

Major
Joined
Feb 18, 2017
It should also be remembered that the Thoroughfare Gap movement had been a flank move by part of Lee's army which disordered the Union defensive scheme precisely because the flank movement (which got into the Union rear areas) was one which Pope did not adequately guard against. That flank movement had taken place only two weeks ago when McClellan marched out of Washington.

We like to draw neat lines under campaigns, and that sort of leads to the perception that they're not as closely related as they are. But Northern Virginia and Maryland are very close together (the gap between the two is less than a week long, shorter than just about any other pair of major campaigns by the same troops in the war) and the memories would still be very fresh, and this colours McClellan's actions during the campaign (and, indeed, Lee's).



As I'll get into when we reach South Mountain in more detail, something that has to be remembered is that Lee has some expectation of how long it will take the Union to reach him, from when they start out of Washington. His actual dispositions during the movement on Harpers Ferry are very vulnerable to the Union threatening them from the east, and when Lee heard of McClellan's move through the Catoctins and towards South Mountain he ordered Jackson to break off the siege and McLaws to try and get his troops out as best he can; this more than anything else indicates Lee cannot have expected McClellan (or the Union army, under whoever it was) to have been threatening them from the east by that time in his operations.
This could have been because Jackson was running late (thus why Harpers Ferry had not yet been taken) but if Lee was designing his operations with a level of coordination so tight that Jackson running a day or two late could completely unhinge his entire operational design then that in and of itself indicates that he was treating his opponents with a dangerous level of contempt...
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
... Lincoln and Halleck visited McClellan on September 2 and gave him command of the defences of Washington, then on September 6 he was given command of the field army.
McClellan described it thus: "On the 1st of September I had been instructed that I had nothing to do with the troops engaged in active operations under General Pope, but that my command was limited to the immediate garrison of Washington. On the next day [2nd of September], however, I was verbally instructed by the President and the General-in-Chief to assume command of General Pope's troops (including my own Army of the Potomac) as soon as they approached the vicinity of Washington; to go out and meet them, and to post them as I deemed best to repulse the enemy and insure the safety of the city." So by the 2nd he was in command of the entire force in and around DC.
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
As for the third point, about getting troops to Pope ... could have marched out earlier ... but that's up to Halleck not McClellan.
It should also be remembered that the Thoroughfare Gap movement had been a flank move by part of Lee's army which disordered the Union defensive scheme precisely because the flank movement (which got into the Union rear areas) was one which Pope did not adequately guard against.

years ago I spent a good deal of time studying the interaction between Pope Halleck and McClellan at the end of August and came to the conclusion that Halleck was the one that screwed everything up. Halleck had given Pope the impression that Halleck had assigned some force from DC to guard Manassas so Pope felt he was secure from the kind of move Jackson did; but this wasnt the case. And McClellan acted as best he could given what Halleck was telling him, but Halleck's directions were fluctuating and unclear. Halleck also bears responsibility for pulling McClellan from the peninsula while pushing Pope further from DC. So in general, I think putting Halleck in charge of everything was the worst thing to happen in August 1862. He also left things in the west ambiguous and open to command confusion.
 

Saphroneth

Major
Joined
Feb 18, 2017
McClellan described it thus: "On the 1st of September I had been instructed that I had nothing to do with the troops engaged in active operations under General Pope, but that my command was limited to the immediate garrison of Washington. On the next day [2nd of September], however, I was verbally instructed by the President and the General-in-Chief to assume command of General Pope's troops (including my own Army of the Potomac) as soon as they approached the vicinity of Washington; to go out and meet them, and to post them as I deemed best to repulse the enemy and insure the safety of the city." So by the 2nd he was in command of the entire force in and around DC.
Per Too Useful to Sacrifice:



McClellan’s restoration to command didn’t mean that Porter escaped unscathed. Lincoln had agreed to investigate Pope’s charges against Porter, and he felt differently about Porter’s usefulness than he did about McClellan’s. On September 5, the president ordered the creation of a court of inquiry to report on the activities of several officers Pope implicated in the cause of his defeat at Second Bull Run. Unlike a court-martial, a court of inquiry acted as a council and did not reach legal decisions. The tribunal of three general officers was overshadowed by the Maryland Campaign, met only three times, and disbanded indefinitely on September 15. It did, however, last long enough to relieve Porter of corps command at a time when McClellan most needed him. Little Mac asked the war department on September 6 to suspend the order “until I can see my way out of the difficulty.”37

McClellan’s “difficulty” arose that same day when Lincoln gave him command of the field army; he needed the experienced Porter. That morning both Lincoln and Halleck called upon McClellan at his home in Washington. Controversy exists as to who said exactly what to the general. Halleck claims that during the discussion Lincoln blurted out, “General you will take command of the forces in the field,” and he did so without any prior knowledge on Halleck’s part. It closely resembled the order of September 2 when Lincoln appointed McClellan to command Washington’s defenses, but no written order followed. The president, however, denied ever giving such an order. Secretary Welles noted in his diary on September 10, “the President assured me that this appointment of McClellan . . . was Halleck’s doing.” Two days later Lincoln reiterated to several members of his cabinet that Halleck had selected McClellan for command. These statements do not comport with those Lincoln made later to Congressman Kelly about McClellan’s restoration being “the greatest trial and most painful duty of his official life.” 38

Halleck's testimony, JCCW:

1616609621312.png
 

Saphroneth

Major
Joined
Feb 18, 2017
McClellan described it thus: "On the 1st of September I had been instructed that I had nothing to do with the troops engaged in active operations under General Pope, but that my command was limited to the immediate garrison of Washington. On the next day [2nd of September], however, I was verbally instructed by the President and the General-in-Chief to assume command of General Pope's troops (including my own Army of the Potomac) as soon as they approached the vicinity of Washington; to go out and meet them, and to post them as I deemed best to repulse the enemy and insure the safety of the city." So by the 2nd he was in command of the entire force in and around DC.
I think the distinction here is that on the 2nd September he's placed in command of the Washington defences and all troops in them, (as opposed to just the garrison itself), but on the 6th September his remit is expanded to include to lead an army out of Washington against the enemy. Before that date, if there was an army taking the field it would not necessarily be under McClellan, and indeed he hadn't been authorized to do so (as his remit was to post troops to defend Washington).
 

Saphroneth

Major
Joined
Feb 18, 2017
Campaign movements, 8th-12th September


On the 8th, McClellan's army made their first advance. In addition to the cavalry screen closing to contact with the Confederate screen (at least at the western end of the line), 2nd and 12th Corps pushed forwards on the main turnpike road with Sykes behind.

It was impossible for the whole Union army to feasibly advance down the one road - if only because armies are longer than we really think about, to the extent that if the whole force tried to fit down a single road it would be dozens of miles long. The empirical corps (~30,000 PFD) is about the maximum size that can fit down a road in a day, so McClellan's force which marched out of Washington would roughly speaking take three roads (though this is based on a typical march, and it is possible to push further; it's not necessarily a good idea, though, as pushing troops too hard results in straggling and the force is less able to fight when it reaches the other end).

Consequently, while Sumner's wing (plus Sykes) move ahead on the Rockville turnpike, Burnside's wing takes the adjacent pike road north out of Washington and move towards the National Road. The cavalry also moves out ahead of them, aiming to make contact elsewhere.

Night of 8th September
Night_of_8th.jpg



On the 9th, the forces of 2nd, 6th and 12th Corps largely remain static while Couch, 1st and 9th Corps push out to form a broader fan. The Confederate cavalry is also pushed in somewhat, while Union cavalry reaches the National Road.

Night of 9th September
Night_of_9th.jpg

This is also the day on which Lee issues Special Order 191, which outlines his plans for the next few days.

Lee's plan is to go after Harpers Ferry. It is worth pointing out here that McClellan had raised concerns about Harpers Ferry being imperilled, and Halleck refused to countenance evacuating the fortification. However, we should consider the totality of what Lee's orders were.

Lee intended for the first of his troops out of Frederick to be Jackson's command, moving on the 10th (Wednesday). That command was to move on the National Road through South Mountain, then cross the Potomac (with the choice of route up to Jackson) and be in position to block escapees from Harpers Ferry by Friday (i.e. the 12th).

Longstreet was to move next, and was to take the same route as far as as getting over South Mountain, where it was to halt just on the far side of the mountain range.

McLaws was to take his division and Anderson's division, and move along the National Road before turning off to the southwest and coming at Harpers Ferry from the northeast.

Walker's division wasn't in Frederick to begin with, and was to move south of the Potomac before coming at Harpers Ferry from the southeast.

Finally, DH Hill's division was to move after the wagon trains, and was to form the army rearguard (moving through the South Mountain gaps on the National Road as well). Stuart was to screen the movement.

The overall goal was to either compel the evacuation of Harpers Ferry, or to compel the surrender of the fortified arsenal.


The first thing we need to notice here is that Lee's orders outline the next few days of operations, but not what he was planning on doing after that. It is quite possible that he was keeping his options open but had not committed to any definite plan.

The second thing is that Lee's plan is very well designed to do what he intends to do (i.e. capture Harpers Ferry) but that it is not well designed to fend off interference from Union forces coming from the east. While the force on the National Road gaps is large enough to defend the gaps, in this conception, the force which is coming at Harpers Ferry from the north is not necessarily large enough to simultaneously defend the gaps and put pressure on Harpers Ferry. It also means that there's some time dependency on how quickly Harpers Ferry is likely to surrender, because (for example) if Lee is expecting it to take until the 13th for Harpers Ferry to surrender then he is expecting the Union to not be able to interfere until that date.

As of the end of the 9th, Lee's intelligence on where the Union could be is limited. The Union cavalry screen was at Clarksburg on the night of the 8th; it's now at Hyattstown, and Union troops could conceivably be as close as Clarksburg and he would not have information different to what he currently possesses.


To turn this around, it is of course impossible for McClellan to know Lee's plans before Lee has actually decided on them; it would be difficult for McClellan to know Lee's plans with any degree of certainty until his cavalry recce has established the minimum information for him to make that deduction. At this point McClellan is at least fairly sure that Lee's not already halfway to Baltimore because the Union cavalry screen has established that he's not on that part of the National Road, but Lee could be doing anything from preparing an active defence of the line of the Monocacy to already on the move west to having the head of his column around New Market. McClellan is doing considerably better than Pope did in pushing out his cavalry to gain a picture of the situation (Pope having managed to miss Longstreet's corps arriving in the area of the Second Battle of Bull Run in spite of having what we could if anything consider an overabundance of evidence) but there's limitations there.







On the next day, the 10th, French's division is formed (not shown) and bolsters Sumner's wing with the first major reinforcement of the campaign. McClellan's leading corps (2nd, 6th, 12th) push out to just behind the cavalry screen, though 9th and 1st Corps do not move; in light of what happens on the 11th however I suspect that this is partly letting their transportation capacity catch up to the actual infantry columns.

Night of 10th September
Night_of_10th.jpg


Lee meanwhile has mostly marched out of Frederick. His main body (which was all his infantry divisions except DH Hill and Walker, and not much of his cavalry) took sixteen hours to pass through the street, and was observed by Steiner as it passed through to be "not more than 64,000 men".

While I do not wish to belabour the point too strongly, I should make clear here that McClellan still has no real way to tell that Lee has done this. The great majority of the Confederate cavalry is screening the movement.




On the 11th, 9th and 1st Corps make major movements out to the National Road and prepare to advance on Fredrick, while the rest of McClellan's army prepares to cross the Monocacy. The Confederate cavalry is pulling back and McClellan may suspect by this point that Lee has moved west in force, but the Confederate army being in western Frederick County is not yet something he can entirely discard.

Night of 11th September
Night_of_11th.jpg


Meanwhile, on Lee's side of things, his forces are running late. Jackson was supposed to be reaching a position where he can intercept escapees from Harpers Ferry by Friday morning, but by Thursday evening he's still some way short. Walker also has a significant distance to go.

On the other hand, there's something else interesting going on. Longstreet has moved up towards Hagerstown, on the border of Pennsylvania.

It is my opinion that this reflects Lee's then-current intention, which was to move into Pennsylvania. Clearing Harpers Ferry would in this interpretation not be simply a lure to try and draw the Union into a field battle but would be to better enable him to keep communications open.
Harpers Ferry not being a lure would also explain why Lee's dispositions leave him vulnerable to the arrival of Union troops.
This is just an opinion however and it's quite plausible that Lee had several options he was considering simultaneously.

This day also sees DH Hill's division march out of Frederick following the wagon trains. Steiner observed this force as well, and called it "8,000", but of DH Hill's division only four brigades actually marched through Frederick (GB Anderson did not), and Steiner's count did not include the cavalry or Walker's division either (as Walker never went through Frederick either).
This means that the infantry portion of Lee's army, minus 13 regiments (i.e. minus about 7%) was seen as 72,000 men. The infantry as a whole should be about 77,500 men by this measure, and the cavalry (about another 13 regiments) should bring this up to about 83,000 by this measure.



The events of the 12th see Lee's army moving towards the goals he's set them, but they're still moving slower than he'd like. McLaws and Anderson are down at the southern end of the Pleasant Valley, and Walker is about to enter the Piney Run Valley (also known as Between the Hills). Jackson is now definitively running late (he should have been in position to intercept Harpers Ferry escapees by now), but has driven much of the troops in the upper Shenandoah to take refuge in Harpers ferry.

Longstreet meanwhile has occupied Hagerstown, and has some cavalry scouting north.

Most of the rest of the Confederate cavalry is holding the passes in the Catoctin mountains, as McClellan's own cavalry has driven Stuart out of Frederick and taken control of the town themselves. Behind this the Union infantry starts to cross the Monocacy with all troops moving forwards.

Back in Washington, meanwhile, Porter has been ordered to reinforce McClellan. The exact details of this are a little shrouded in confusion, because of ambiguity that existed at the time.

When McClellan left Washington, Porter was where he'd been placed by McClellan - in command of the defences south of the Potomac by virtue of his seniority, where he disposed of (by his morning report of the time on 10th September) more than 23,000 troops. His 5th Corps (consisting at this point only of Morell's division, since Sykes' division was detached) was part of this force, but it also included other troops.

On the 9th of September, Halleck informed Banks (Banks commanding Washington's fortifications as a whole) that Heintzelman was to be put in command of the troops south of the Potomac on the 10th, as per orders from the President. This information reached McClellan via a telegraph from Porter (where Porter informed McClellan that the troops for the defences south of the Potomac were nearly all in position, and that Heintzelman was to take command of those defences "tomorrow").
McClellan objected to Banks about this, apparently not knowing that it was the result of a Presidential order, but the reason for Lincoln doing it is not entirely clear. Lincoln reportedly spoke to Welles about an unspecified "remedy" for Porter's transgressions, so it may have been that Porter was held repsonsible for Pope's defeat and not trusted, or it may have been that the glory from repulsing an attack on Washington itself (something feared as entirely possible, specifically in the form of a column coming up from Richmond) was not to be allowed to go to Porter.

Meanwhile,on the evening of the 11th, Lincoln informed McClellan that 5th Corps was being ordered forwards, with Lincoln saying "Porter reports himself 21,000 strong, which can only be by the addition of new troops" and Halleck reporting on the 13th that Porter had departed with "over 20,000" the day before.

En route through Washington on the 12th (as he had to march from south of the Potomac) Halleck offered Porter an extra division from the southern defences of Washington, which Porter accepted (requesting Humphreys as the commander) but this division did not leave Washington for another couple of days; thus only Morell's division actually left Washington with Porter on the 12th.

What is most interesting about this is that Halleck and Lincoln apparently believed or professed that Porter's strength consisted of the totality of his morning report from the 10th (i.e. over 20,000 men), rather than just the much smaller force of Morell's single division. This may have had a significant impact on their perception of the strength McClellan had at the battle of Antietam.

Interestingly Banks' September 11 report listing the strengths in the Washington defences listed Porter's 5th Corps as having 21,000 men (which is probably where Lincoln got his number from) and as being part of the Washington defences on that date; Heintzelman's 3rd Corps was listed as 16,000, and Sigel's 11th Corps was listed as 9,800. This actually renders the entire September 11 report suspect, since Banks was cetainly in a position to know that this was not a correct statement of the strength of 5th Corps in the Washington defences; it's an open question whether Banks himself honestly believed the information he put in the report, or whether he was induced to alter it, or whether someone else altered it after the report was submitted. All we can really say for sure is that the report was incorrect, and that we should probably use the September 20 report as the basis for any calculations on the strength of the defences of Washington in the Maryland Campaign.


Regardless of this controversy, Morell's division was en route, but it was still some distance away from the front of the advancing army on the night of the 12th and would take some days to catch up. It moved fast, though - moving through an area which was known to be safe aided this greatly.

Night of the 12th
Night_of_12th.jpg



The next day in the campaign is the 13th September, which is the day of the discovery of the Lost Order. I'll break my analysis at noon of the 13th.

For Lee, this is the day when Jackson finally reaches Harpers Ferry and the siege actually begins. The battle at Maryland Heights had seen some skirmishing on the 12th (the day when McLaws was supposed to take the Maryland Heights) but the serious fighting only began in the morning of the 13th. Walker arrived around 10AM and Jackson around 11AM, and they found that the commander of the defences (Miles) had failed to occupy the key positions around Harpers Ferry in sufficient strength - by which I mean that Miles hadn't really defended the key terrain at all.

Something that should be pointed out here is that even though Lee is running behind schedule, it's not by much - about a day, really. You can consider how tightly you think Lee was willing to cut his margins on your own, I think.


Over the morning much of the Union army concentrated on Frederick - which was just about the only way the road network permitted armies to move - and the 9th Corps got right of way through the one road that had to be used, meaning that elements of other corps had to wait. McClellan himself entered Frederick around 11AM, directing the 9th Corps to keep moving west over the Catoctins - though there was something of a traffic jam in Frederick itself. The immediate objectives for McClellan's force at this point were the passes over the Catoctins at Braddock Heights (where the National Road crosses the Catoctins) and the Jefferson Pass (further south where the next-best road crosses the Catoctins - the roads are the same road in Frederick but divide west of town). In both cases the passes were held by Stuart's cavalry, and McClellan directed cavalry against them with a division each of 9th Corps.


Meanwhile the 27th Indiana ends their march around noon, and someone finds some cigars.
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
When McClellan left Washington, Porter was where he'd been placed by McClellan - in command of the defences south of the Potomac by virtue of his seniority...
What does the last part mean? He was junior to Heintzelman and Sigel.

where he disposed of (by his morning report of the time on 10th September) more than 23,000 troops. His 5th Corps (consisting at this point only of Morell's division, since Sykes' division was detached) was part of this force, but it also included other troops.
Also included the brigades that would form Humphreys division, so the 20k-23k number makes sense

...
Interestingly Banks' September 11 report listing the strengths in the Washington defences listed Porter's 5th Corps as having 21,000 men (which is probably where Lincoln got his number from) and as being part of the Washington defences on that date; Heintzelman's 3rd Corps was listed as 16,000, and Sigel's 11th Corps was listed as 9,800. This actually renders the entire September 11 report suspect, since Banks was cetainly in a position to know that this was not a correct statement of the strength of 5th Corps in the Washington defences...
So first you say that Porter claimed more then 23,000 troops but than bash Banks for saying that it was 21,000?
On what do you base that Banks statement was really incorrect?
 

Saphroneth

Major
Joined
Feb 18, 2017
What does the last part mean? He was junior to Heintzelman and Sigel.
My understanding is that at that time Porter was the senior officer south of the Potomac. That changed to Heintzelman over the course of the 10th.

That could of course be incorrect, but the numbers don't work out for there to have been Morell's division plus another corps plus other troops south of the Potomac.

Also included the brigades that would form Humphreys division, so the 20k-23k number makes sense

So first you say that Porter claimed more then 23,000 troops but than bash Banks for saying that it was 21,000?
There are two different categories here.

The first one is "what troops was Porter commanding on the morning of the 10th", which is Morell's division (of 5th Corps) plus other troops in the Washington defences south of the Potomac that were not assigned to 5th Corps.

The second one is "What was 5th Corps on the morning of the 10th", which is Morell's division (of 5th Corps) plus possibly Sykes' division (though Sykes' division was detached on that date and Porter couldn't have included it on the consolidated morning report).


It's sort of like how Heintzelman commanded over 70,000 troops on 31 October, but that doesn't mean 3rd Corps was 70,000 strong on that date.

If Banks' report ascribing 21,000 men to 5th Corps in the Washington defences on the 11th was correct (the report is headlined Troops for defense of Washington), then it would mean that there were 21,000 men in 5th Corps in the Washington Defences at that time. But there weren't; Humphreys wasn't assigned to 5th Corps until after that date, while Sykes wasn't in the Washington Defences.




So "There are 21,000 men in 5th Corps" is perhaps true on the 15th (once Humphreys' division has formed and been assigned to 5th Corps), but it isn't true on the 11th; "There are 21,000 men in 5th Corps in the Washington defences" isn't true by any definition on any date; "Porter commands 23,000 men in the Washington defences on the morning of the 10th September" is true.

Those would be:

Sykes​
Morell​
Whipple (then Humphreys)​
Other forces south of Potomac​
Total​
~5,000​
~8,000​
7000​
8000​
5th Corps on 10th​
Yes​
Yes​
No​
No​
13000​
Porter’s command with him on 10th​
No​
Yes​
Yes​
Yes​
23000​
5th Corps in Washington defences on 10th​
No​
Yes​
No​
No​
8000​
5th Corps on the 14th​
Yes​
Yes​
Yes​
No​
20000​
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
My understanding is that at that time Porter was the senior officer south of the Potomac. That changed to Heintzelman over the course of the 10th.

That could of course be incorrect, but the numbers don't work out for there to have been Morell's division plus another corps plus other troops south of the Potomac.
You are incorrect. For example on the 7th messages were being sent to Porter at Fort Corcoran and Heintzleman at Fort Lyons, both south of the Potomac. And around that time Sigel was reported as on the Virginia side near Chain Bridge. So all three corps were south of the river at the time yet none of them were in command of everything south of the river until the order to Heintzelman.

And the numbers work out just fine - Porters command (5th Corps) after Sykes was detached consisted of Morell and Whipple. Sturgis had been assigned to him, then relieved, his position taken over by Whipple, from whom two brigades would be detached to form a new division under Humphreys, all the while part of the 5th Corps. And the aggregate for Morrel's division at the time was 17,000. So your telling me that before it left Washington, more than 1/2 of it was already absent?
 

Saphroneth

Major
Joined
Feb 18, 2017
You are incorrect. For example on the 7th messages were being sent to Porter at Fort Corcoran and Heintzleman at Fort Lyons, both south of the Potomac. And around that time Sigel was reported as on the Virginia side near Chain Bridge. So all three corps were south of the river at the time yet none of them were in command of everything south of the river until the order to Heintzelman.

I see. In which case that presumably means there was almost nobody north of the Potomac, given the nature of Banks' 11th September report!


And the numbers work out just fine - Porters command (5th Corps) after Sykes was detached consisted of Morell and Whipple. Sturgis had been assigned to him, then relieved, his position taken over by Whipple, from whom two brigades would be detached to form a new division under Humphreys, all the while part of the 5th Corps. And the aggregate for Morrel's division at the time was 17,000. So your telling me that before it left Washington, more than 1/2 of it was already absent?
Do we have the orders for Whipple or Sturgis being assigned to 5th Corps? (I mean as distinct from their being assigned to Porter, since the difference between "Porter's command" and "5th Corps" is the whole of the issue here.) Porter said that Morell's division was the only one he had the right to take, while if Whipple was part of "5th Corps" then he'd have been able to take both Morell and Whipple.

It's certainly the case that Porter did not depart with "over 20,000" on the 12th of September, in any meaningful sense. 5th Corps as of September 20th was 19,500 PFD, but that includes Sykes (who didn't march with Porter), and Humphreys didn't leave Washington on the 12th of September.


As for the aggregate, well...
Morell's division at Antietam consisted of 19 regiments and 4 batteries. For them to have an aggregate present and absent (which is the category you're talking about) of 17,000 then the companies making up the regiment (195 of them) would have to average 87 men each - which seems to fit.
For example, this would make the 6th Corps, with about 270 companies, number 23,500 instead of their actual strength PFD of 12,930, and indeed on the 20th September return has the 6th Corps aggregate present and absent total 23,356.

Morell's division was badly hit at Second Bull Run (it goes from 5154 to 3808 Effectives over the last few days of the campaign, which is the worst % loss except in McDowell's Corps - note that 1st Corps on the 20th lists 12,237 Present For Duty and 31,583 Aggregate Present and Absent, though this also includes the hammering it took in the Maryland Campaign itself - as of the start of the fighting it seems to have been at ca. 50% of AP&A as PFD, with a bit over 15,000 men going into South Mountain and the AP&A consequently somewhat higher as well) and it seems quite credible to me that it would be depleted significantly as a result.
 

Saphroneth

Major
Joined
Feb 18, 2017
Banks' note of September 11th lists:

Garrisons 15,200
1st (Sigel), 3rd (Heintzelman), 5th (Porter) Corps, 46,800 as
Porter 21,000
Sigel 9,800
Heintzelman 16,000
City guards and provisional brigades 10,500
Total "for duty" 72,500.

So this is clearly PFD (as it says "for duty").

The report of September 20th lists in the same categories, as PFD:

HQ/staff/escorts 459
Garrisons 19,349
City Guards total 3,638
3rd Corps total 17,127
11th Corps total 10,299
Whipple's division 3,834
Casey's division 6,368
Stoneman's corps of observation upper Potomac 4,452
Cav Bde 1,700
The convalescents, stragglers and recruits are 3,984

With a total of 71,210. This implies that the increase in new regiments arriving almost exactly matches the strength of troops which left between the two dates (Morell and Humphreys, plus any cavalry which left).


Now, in most cases the September 20 report also includes a mention of the AP&A and the AP&A last return.

Those are:

HQ/staff/escorts 755 up from 3
Garrisons 23150 up from 17745
City guards 6294 down from 8168
3rd Corps 29,599 up from 22,503
11th Corps 19,337 up from 17,087
Whipple 5,610 down from 9,869
Casey 7,079 up from 9,869
Stoneman 6,766 up from 5,266
And the cavalry is 2,723 down from 4,255.
The convalescents, stragglers and recruits are 6,526 AP and also AP&A, and have no previous.


(Stoneman and the cavalry add to 9,500 almost exactly in both cases, which may or may not be indicative)


Overall increase in AP&A (including convalescents etc.) is 18,500, of which 12,000 can't possibly result from double counting of convalescents and stragglers.


What this means is that the change from September 11 to September 20 (principally the departure of Morell and Humphreys, plus the addition of new troops) was NO change in PFD but a LARGE increase in AP&A.

We would expect Morell and Humphreys, taken as a unit, to represent a LOT of AP&A relative to their PFD because Morell's division at least was very hard hit (and was an "older" division). This would mean a LARGER decrease in AP&A than in PFD. (For example, if Morell's division represents 17,000 AP&A and 9,000 PFD, and Humphreys' division was 7,000 AP&A and 7,000 PFD, then the drop in AP&A relative to PFD would be -8,000)
We would expect the regaining of straggled troops from 3rd and 11th Corps to result in NO change in AP&A, but an INCREASE in PFD.
We would expect new troops coming in from elsewhere to reflect mostly quite "full" regiments, which would have a high PFD relative to their AP&A.
We can know that Humphreys is reflected becase of Whipple's drop in AP&A.


Therefore, there's something odd going on if the September 10 report is correct and embraces all units as PFD.



I should also note that as of August 10 Morell's division had 6,174 PFD and 9,943 AP&A (down from 14,798 AP&A on 20 June). It actually looks like it having 17,000 AP&A on September 10 might be flat out impossible! (Perhaps the 17,000 AP&A refers to the entire force of reinforcements that Porter took with him).
 

NedBaldwin

Major
Joined
Feb 19, 2011
Location
California
I see. In which case that presumably means there was almost nobody north of the Potomac, given the nature of Banks' 11th September report!

Do we have the orders for Whipple or Sturgis being assigned to 5th Corps? (I mean as distinct from their being assigned to Porter, since the difference between "Porter's command" and "5th Corps" is the whole of the issue here.) Porter said that Morell's division was the only one he had the right to take, while if Whipple was part of "5th Corps" then he'd have been able to take both Morell and Whipple
From Banks report, we see a number of forces that were north of the Potomac (Woodbury, Haskin, Wadsworth, Casey). In addition, McClellan has a field army north of the Potomac.

I know of no orders regarding a "Porter's command" that is different than the 5th Corps. Orders on the 7th are addressed to Porter, "Commanding Fifth Corps" and the same day orders state that Sturgis is relived from duty with the "Porter's Corps".
 
Top