1862 Loudoun Valley campaign

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
The order to DH Hill and Walker to go to Upperville is dated 22nd. I think it's reasonable to place them there on the 24th.
 

Saphroneth

Major
Joined
Feb 18, 2017
Something else which I find interesting is to ask the question about the Loudoun Valley campaign - what exactly would Lee's next step have been? (And, subsequently, how would the campaign have developed.)

Based on Lee's historical correspondence, it is clear as day that he wanted Jackson to move up the Shenandoah Valley to Swift Run Gap. He asked Jackson to do this often; it is not credible that he would have asked if he didn't want Jackson to do this. The fact that Jackson doesn't move for almost another two weeks after McClellan is fired may or may not hold if McClellan is retained in command, but it's important information (and indicates Lee may not actually be able to get Jackson moving in any direction), but if Lee's commands are implemented then Jackson will be marching south (probably along the Valley Pike) towards Swift Run Gap.

Lee's plan for Longstreet, on the other hand, is something he can actually have Longstreet implement. The way that detachments have been moving south towards Madison may indicate part of Lee's plans - i.e. fall back via Madison to unite with Jackson - but the way events are developing (with McClellan further south than Lee was expecting and Jackson not moving) mean that Lee may change his mind.

McClellan was still on the move when fired, and at the very least he would collect at Warrenton; the fact he had 9th Corps capture a bridge over the north fork of the Rappahanock is suggestive of what his subsequent intent was, as is how he had his cavalry shifting from covering the mountain passes to a wide arc south of his main army (Gregg was at Waterloo Bridge screening that crossing, Bayard was at Rappahanock Station holding that bridge, and Averell/Farnsworth - Pleasonton's brigade - was around Little Washington.) Now with six corps (1st 2nd 3rd 5th 6th 9th) and resupply at Warrenton McClellan is in a good position to go after Culpeper.
This means that it's likely that within a few days of the 7th November Lee will be faced with what to do when Culpeper is threatened, and it seems to me that Lee would pull back - either to an interim line along Robertson's River (with the left at Madison Court House, where Walker has gone) or to Gordonsville.

It's here that Lee would have to make the big choice. If Longstreet is at Gordonsville and McClellan starts crossing the Rapidan in force, and Jackson hasn't yet joined with Longstreet, Lee has a choice between letting McClellan march on Richmond or giving up his communication with Jackson.


Lest anyone think that McClellan timidity would prevent such a move, as of the 7th November McClellan knew where all of Jackson's divisions were; he thus knew that only about half the Confederate army was around Culpeper. On the 17th September McClellan was willing to go after the whole Confederate army, no matter how big he thought it happened to be; now half of it is days away and the other half has suffered casualties at Antietam.*
Meanwhile the supply situation is at least acceptable; most of McClellan's units crossed the Potomac around the 30th October and then marched south relying primarily on flying-column supply until Warrenton was taken and they reconcentrated around there on the 8th, so McClellan's force can operate largely on the supply they have with them for on the order of nine days.



* ed: see next post.
 
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Saphroneth

Major
Joined
Feb 18, 2017
Further to the above, I thought I'd look at Union strengths.


Compared to the Maryland campaign, McClellan is also stronger.
At Antietam McClellan's reports (which include some units not actually at the battle) have 87,164 men PFD, before casualties; including Couch and Humphreys his total manoeuvering force before casualties was about 103,000 PFD.
On November 10th the total strength of the Union army around Warrenton (i.e. the "Total army in the field" minus 12th Corps at Harpers Ferry and Morell on the upper Potomac) is
6755 - 573 - 224 officers (so 5958)
and
123797 - 10757 - 4220 men (so 108,820)
For a total of 114,778 officers and men PFD.
This however does not include one division of 3rd Corps, which had not yet formally arrived (Stoneman's division and Whipple's division are counted individually, but the third division of 3rd Corps is still under the "defences of Washington" category on this report). The November 20th return is missing, but the December 10 return for Fredericksburg gives the strength of the Center Grand Division (3rd and 5th Corps) as 40,396 PFD; with the strength of 5th Corps on November 10 being 19,073 this implies a total strength of 3rd Corps of about 21,300 PFD.
Whipple's division is 4,109 and Stoneman's division is 9,276, implying that the missing division of 3rd Corps totals about 7,900 PFD all told.**
This indicates that McClellan's strength is about 122,500 PFD - i.e. he is about 20,000 troops stronger than in the Maryland Campaign, and knows his enemy is both weaker (due to casualties) and divided (as he knows where Jackson is and has a good idea where Longstreet is).


This is the situation as actually obtained. But what would the worst case have been for McClellan, if he'd launched on Loudoun earlier and if - as one cannot deny had happened before for McClellan - his reinforcements from Washington (to whit, 3rd Corps) had not actually arrived?

To get this, we can simply take the total number here (122,500 PFD) and subtract off the troops which in this hypothetical McClellan would not have available.

1) If Longstreet has not yet begun moving south, or if there is still a threat to the upper Potomac in some other way (i.e. if he'd moved earlier), McClellan needs to leave 5th and 6th Corps in place to cover the river. These forces total 19,073 PFD (5th Corps) and 25,979 PFD (6th Corps), costing McClellan a total of 45,000 troops.
2) Whipple's division was available before the move, but the rest of 3rd Corps was not necessarily available. This would cost McClellan another 17,200 PFD (3rd Corps strength - Whipple).

This would give McClellan a total of only 60,300 in his moving column. This is enough to fight one Confederate corps, certainly, but not both - and it was only that same August that Lee had managed to combine his corps unexpectedly by fast marches, so it was a definite risk.

The shift in available strength is striking, and I believe it's why McClellan initially resisted the Loudoun plan. Going into the Shenandoah would let him use 1st, 2nd, 5th, 6th, 9th and 12th Corps for sure, plus the units which were historically left for Morell (for a total of about 117,000 PFD).

For comparison Lee's own November 10 report came to about 70,000 PFD (by his measure), with both infantry corps being about 32,000 PFD and the rest cavalry.


** as a point of mild curiosity, the GCACW module for Burnside's November campaign actually misses this, and gives 3rd Corps only about 13,000-14,000 men PFD - they missed that Stoneman and Whipple were not all of 3rd Corps
 

Jamieva

Captain
Forum Host
Joined
Feb 7, 2006
Location
Midlothian, VA
Jackson is looking for a opportunity to strike through the lower Valley gaps and get in Mac's flank or rear. I really think Jackson gets too micro focused on his situation without contemplating the overall strategic picture, and how far away he is from Longstreet if he is needed. He most likely is relying on Mac's typical slow movement that he could outmarch the AotP if needed, but it was definitely playing with fire. It also speaks volumes that as you point Lee gives the order to move south more than once and Jackson doesn't budge. Typically historians would be hyper critical of a subordinate ignoring a direct order like that.

Thanks for the daily maps they are a huge help
 

Saphroneth

Major
Joined
Feb 18, 2017
Jackson is looking for a opportunity to strike through the lower Valley gaps and get in Mac's flank or rear. I really think Jackson gets too micro focused on his situation without contemplating the overall strategic picture, and how far away he is from Longstreet if he is needed. He most likely is relying on Mac's typical slow movement that he could outmarch the AotP if needed, but it was definitely playing with fire. It also speaks volumes that as you point Lee gives the order to move south more than once and Jackson doesn't budge. Typically historians would be hyper critical of a subordinate ignoring a direct order like that.
The interesting thing is that not only is it not even the first time Jackson has done this (I can think of at least two other cases - once during the first couple of the Seven Days up to Beaver Dam Creek, where Jackson basically ignored his orders to come in on Porter's flank, and then the second one during the Maryland campaign where Jackson ignores his orders to break off the Harpers Ferry siege) but in this case it might have had a serious negative impact.

Specifically, your mention of marching speed kind of speaks to the problem, which is that McClellan has moved fast enough that the Loudoun Valley is no longer a vulnerable point for McClellan. Once 1st Corps has taken Warrenton the Union supply route is the railways coming out of Washington, and his supply line is on the eastern side of the Bull Run mountains; Jackson has a long way to go to interrupt it and a very long way to go in order to do so, get back to safety, and then rejoin with Lee.

If Jackson's movements are all perfectly efficient, then for AP Hill (his largest division) to go out of Snickers Gap, hit the closest point on the Orange and Alexandria railway, return to the Valley, march via Swift Run Gap and then reach Hanover Junction would be a journey of two hundred and twenty-five miles.

For McClellan to march from Warrenton, via Culpeper, Orange and Fredericksburg to Hanover Junction (which is about the longest route he could realistically be taking to get there) would be one hundred and twenty miles. In other words, half as far.

The real crisis point for Lee's army though is when McClellan reaches strike range of Gordonsville. To get to Gordonsville even without striking at McClellan's supply line Jackson has to move over a hundred miles; to reach Orange, McClellan has to move forty.
At this point, Longstreet can either stay at Gordonsville and get hit, or move to Hanover Junction (and be cut off from Jackson), or move southwest from Gordonsville (and give McClellan a clear run at Richmond).
 

Bryce

Private
Joined
Jun 2, 2011
Location
Washington, D.C.
Using this as a placeholder. There will be a c span video debuting this weekend with a talk from the Emerging Civil War Symposium. I want to use that as a tool to talk more about these actions. They are often overlooked. Most books about the eastern theater go straight from Antietam, the Mac/Burnside transition and then Fredericksburg.

Much like the actions between Gettysburg and the winter of 64-65 that Jeffrey Wm Hunt has covered in his books so well, these are movements that could use more study.


there are two things you might want to look at. First, Patrick Brennan published an article in north and south years ago about the cavalry actions in October and November 1862 in Loudoun county. More recently David lowe of the NPS published a book on those operations. I can put you in touch with David and with Patrick if you would like.
 
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