Brigade / Division / Corps Sizes

[tony_gunter]

i notice in many battles, sizes of troops groupings are quite different.

Many Confederate brigades were nearly rhe size of a Federal Division. Confederate divisions were somewhere between a division and a corps. And when battles were large enough to match a Confederate corps vs a Federal corps such as at Chancellorsville, the Confederates enjoyed overwhelming numerical superiority.

What was the origin of the difference in sizes for brigade, division, and corps, and how did this affect the performance of the two sides?

 

[Cavalier]

@Saphroneth Thanks, was wondering about that.

John

 

[Saphroneth]

Something that was so standard at the time it's often not mentioned is that the drill book expects you to be using equalized companies - all the same size. This meant that men had to be moved on a temporary basis from large companies to small ones.

So everyone would be used to the idea that they get which company they're in for the day's combat purposes, which would potentially be different from their administrative company. Combining regiments for a tactical battalion would just be doing this starting with more than one regiment.

 

[Luke Freet]

i notice in many battles, sizes of troops groupings are quite different.

Many Confederate brigades were nearly rhe size of a Federal Division. Confederate divisions were somewhere between a division and a corps. And when battles were large enough to match a Confederate corps vs a Federal corps such as at Chancellorsville, the Confederates enjoyed overwhelming numerical superiority.

What was the origin of the difference in sizes for brigade, division, and corps, and how did this affect the performance of the two sides?

On paper a standard infantry regiment would stand at around 1000 officers and men at full strength. However, disease plagued the armies, and so they rarely if ever fielded such a strength in the field. Hence why almost always units in the field turn out to be under strength upon going into battle. Other factors play a role btw but disease is the big one.

Anyway, as for why the rebels often had more manpower unit wise compared to their union counterpart, it had to do with the fact the Confederates started conscription in April 1862, wheras the Union didn't until 1863. This meant that veteran rebel regiments could receive replacements for losses. Since the north initially relief on volunteers only, Union recruiters would more often than not try to form new regiments rather than recruit for pre-existing ones.

Also, organizationally, the Union armies were more standardized. Most federal divisions had two to four brigades per, and two to three divisions per corps. Whereas many rebel divisions had four to five brigades per.

 

[Saphroneth]

One particularly notable factor is indeed the huge Rebel divisions - though, tellingly, these often operated tactically as "demi divisions", with two formations of 2-3 brigades each.

Consider this:

During the Seven Days, the Union corps had this number of brigades.

2nd: 6
3rd: 6
4th: 5 (Peck's division had been cut to 2 bdes owing to casualties, it started as 3.)
5th: 8.5 (Sykes' division was small, Warren's bde had only 2 regiments in it! This is still the largest single Union corps though.)
6th: 6


And the Confederate divisions had:


Jackson's Command:
Whiting: 2
Jackson: 4
Ewell: 3

These ones are "normal", averaging three brigades. Jackson's command is basically a big corps by the Union standards at the time.

Magruder's command:
1st Division: 2
McLaws: 2
Magruder: 2

These are small divisions which are combined into a single larger command. Magruder's command is basically a corps, at 6 bdes.


DH Hill: 5
Longstreet: 6
Huger: 5
AP Hill: 6

These are each basically corps by Union standards at the time, they just don't use the term.

And there's another spare brigade or two.

There would not really be any definitional problem with describing the Seven Days as a fight between five Union corps and six Confederate ones. In terms of regiments the same thing is going on - including army level troops and consolidating everything into them, the five Union corps average about 350 companies each and the six Confederate formations I've called "basically corps" average about 358 companies each.

 

[67th Tigers]

@Saphroneth I had the impression they operated as two battalions, one of 300 men and the other of 240. I have no idea how this would have worked while maneuvering on the battlefield however.

They were consolidated into a battalion except for the 28th Mass. The brigade was essentially a regiment.

28th Mass: 224 engaged (offrs and men)

63rd NY: 75 engaged (2 coys)
69th NY: 75 engaged (2 coys)
88th NY: 90 engaged (2 coys)
116th PA: 66 engaged (3 coys, one coy serving as divisional provost)
Consolidated Battalion = 306 engaged

 

[67th Tigers]

These are each basically corps by Union standards at the time, they just don't use the term.

Because the law permitting the formation of Army Corps hasn't happened yet. In the east we thus got some very big divisions, and out west the main army comprised multiple departments, and each Corps was nominally a separate Army (Army of Mississippi, Army of Mobile and Army of Central Kentucky).

 

[Rhea Cole]

@Saphroneth I had the impression they operated as two battalions, one of 300 men and the other of 240. I have no idea how this would have worked while maneuvering on the battlefield however.

@Rhea Cole I believe that the reason the Brigade's previous commander, General Meagher, resigned was because he requested permission to return to New York and recruit more troops for the original three N.Y. regiments but was refused.

John

Of course we are barely scraping the surface of this topic. There is the constant leaking of CSA cavalry troopers wandering the countryside looking for remounts… for years at a time in some cases. Combined with Governor Brown's Army of Georgia that sprouted innumerable Colonels, Majors, Captains & Lieutenants… not so many gentleman privates… that withheld thousands of replacements from the Army of Tennessee.

 

[Cavalier]

@67th Tigers Ah ha, thanks for clearing that up for me.

John

 

[Stryker65]

This is true. The 32nd Kentucky was consolidated with the 22nd Kentucky in 1862, not too long after Perryville.

I don't think it was...The 22nd Kentucky was a XIII Corps regiment, and the 32nd was a XXIII Corps regiment. I don't believe the two regiments ever served together at all

 

[GELongstreet]

Great differences in corps sizes were not new. During the Napoleonic Wars many French corps were somewhat comparable to corps in the civil war and likewise fluctuated in strength a lot. All numbers varied, from the present battalions of the regiments (permanent) to the divisions. When allies provided troops, voluntarily or not, their integration into corps led to size differences, too. The larger allies at times provided full corps on their own (Austrians, Italians, Polish, various Germans) that obviously varied. In some instances a few corps were enlarged to ridiculous size, e.g. during the invasion of Russia. Looking at cavalry Murat commanded a cavalry reserve that eventually was equal to the other corps but it later it was split up (while overall more cavalry was organized). The resulting reserve cavalry corps were, like in the civil war, much smaller than the infanty type.

 

[huskerblitz]

I don't think it was...The 22nd Kentucky was a XIII Corps regiment, and the 32nd was a XXIII Corps regiment. I don't believe the two regiments ever served together at all

I didn't say they served together. But they were consolidated, though it was in late '61, not 1862.

 

[67th Tigers]

The 22nd Kentucky (mustered in 12th December 1861) was consolidated with the 7th and 19th on reorganisation into a veteran regiment (7th Kentucky Veteran) at the expiry of their term of service in 1864. What Rhea is describing is apparently the men from two different recruiting camps made into a single regiment at mustering in. There is no Colonel Wilson listed as having served, and only one Lt Col named Wilson - that of the 47th Infantry.

The 32nd Kentucky was a 9-month militia unit which only raised 8 coys, and the coys mustered out in a staggered fashion as they reached their 9 months. The regiment was never consolidated.

 

[Stryker65]

@huskerblitz Yes, that was just a recruiting consolidation. Some of those were even crazier; here's how the 178th New York was organized:

Essentially, the 178th was formed out of 8 forming infantry regiments and 3 veteranizing infantry regiments.

 

[huskerblitz]

The 22nd Kentucky (mustered in 12th December 1861) was consolidated with the 7th and 19th on reorganisation into a veteran regiment (7th Kentucky Veteran) at the expiry of their term of service in 1864. What Rhea is describing is apparently the men from two different recruiting camps made into a single regiment at mustering in. There is no Colonel Wilson listed as having served, and only one Lt Col named Wilson - that of the 47th Infantry.

The 32nd Kentucky was a 9-month militia unit which only raised 8 coys, and the coys mustered out in a staggered fashion as they reached their 9 months. The regiment was never consolidated.

Alright, I was just picking up the term 'consolidated'. I've researched the 22nd Kentucky for years now so I know their history. Not much of the 32nd or many other state regiments.

 

[13 IL Cav & 64 GA Inf]

Ti notice in many battles, sizes of troops groupings are quite different.

Many Confederate brigades were nearly rhe size of a Federal Division. Confederate divisions were somewhere between a division and a corps. And when battles were large enough to match a Confederate corps vs a Federal corps such as at Chancellorsville, the Confederates enjoyed overwhelming numerical superiority.

What was the origin of the difference in sizes for brigade, division, and corps, and how did this affect the performance of the two sides?

The origins of troop groupings were from the U.S. Army before the war. When I have looked at this before, a Brigade would ideally be 4,000 for both U.S. and Confederates, BUT more typically ran from 1,500 to 2,500, especially late in the war. A Confederate Division was supposed to be about 10,000 but often ran from 6,500 to 10,000. A Union Division was supposed to be about 12,000 but usually ran from 7,500 to 9,000. A Union Corps was SUPPOSED to be 22,500 to 30,000 BUT was usually only 13,000 to 18,000. A Confederate Corps was SUPPOSED to be 16,000 to 20,000 BUT was usually 12,000 to 18,000. This information is from studying this topic personally a few years ago and putting together information that is publicly available, and it may not be totally accurate although it has served me well as reference for years.

 

[Saphroneth]

A Union Division was supposed to be about 12,000 but usually ran from 7,500 to 9,000.

Or a lot smaller. At Gettysburg there's about 19 infantry divisions on less than 100,000 men PFD in infantry-artillery formations.

 

[13 IL Cav & 64 GA Inf]

On paper a standard infantry regiment would stand at around 1000 officers and men at full strength. However, disease plagued the armies, and so they rarely if ever fielded such a strength in the field. Hence why almost always units in the field turn out to be under strength upon going into battle. Other factors play a role btw but disease is the big one.

Anyway, as for why the rebels often had more manpower unit wise compared to their union counterpart, it had to do with the fact the Confederates started conscription in April 1862, wheras the Union didn't until 1863. This meant that veteran rebel regiments could receive replacements for losses. Since the north initially relief on volunteers only, Union recruiters would more often than not try to form new regiments rather than recruit for pre-existing ones.

Also, organizationally, the Union armies were more standardized. Most federal divisions had two to four brigades per, and two to three divisions per corps. Whereas many rebel divisions had four to five brigades per.

Quite a few Confederate regiments were formed with only 400 to 450 men, especially from late 1863 to the end of the war.

 

[13 IL Cav & 64 GA Inf]

One particularly notable factor is indeed the huge Rebel divisions - though, tellingly, these often operated tactically as "demi divisions", with two formations of 2-3 brigades each.

Consider this:

During the Seven Days, the Union corps had this number of brigades.

2nd: 6
3rd: 6
4th: 5 (Peck's division had been cut to 2 bdes owing to casualties, it started as 3.)
5th: 8.5 (Sykes' division was small, Warren's bde had only 2 regiments in it! This is still the largest single Union corps though.)
6th: 6


And the Confederate divisions had:


Jackson's Command:
Whiting: 2
Jackson: 4
Ewell: 3

These ones are "normal", averaging three brigades. Jackson's command is basically a big corps by the Union standards at the time.

Magruder's command:
1st Division: 2
McLaws: 2
Magruder: 2

These are small divisions which are combined into a single larger command. Magruder's command is basically a corps, at 6 bdes.


DH Hill: 5
Longstreet: 6
Huger: 5
AP Hill: 6

These are each basically corps by Union standards at the time, they just don't use the term.

And there's another spare brigade or two.

There would not really be any definitional problem with describing the Seven Days as a fight between five Union corps and six Confederate ones. In terms of regiments the same thing is going on - including army level troops and consolidating everything into them, the five Union corps average about 350 companies each and the six Confederate formations I've called "basically corps" average about 358 companies each.

If you redefine Corps to equal out things, it still does not account for the overwhelming advantage in troop strength that the Union had.

 

[Saphroneth]

If you redefine Corps to equal out things, it still does not account for the overwhelming advantage in troop strength that the Union had.

What do you mean, an overwhelming advantage in troop strength? Where does the overwhelming advantage in Union strength come from?

The Confederates at the Seven Days have more regiments than the Union, more brigades, they have more companies, they have the same organizational structure as the Union and have more officers - and they're complaining about not having enough officers for their men, which the Union aren't doing.

So why do you say the Union has an overwhelming advantage in troop strength at the Seven Days?

 

[Luke Freet]

Quite a few Confederate regiments were formed with only 400 to 450 men, especially from late 1863 to the end of the war.

Not really, at least not the newer ones. I believe the 64th Georgia fielded 800 officers & men at Olustee in February 1864, a few months after formation. Of course, later in the year, the regiment only hovered around 200 officers & men, and even lower afterwards. When the 63rd Georgia joined the Army of Tennessee in May 1864 for the Atlanta Campaign, it numbered 814 effectives, not counting officers. That is almost as many officers & men total that the 26th North Carolina had at Gettysburg.