An acquaintance with the structure of Civil War armies is helpful in understanding the battle of Gettysburg.
The basic military unit used in both the Northern and Southern armies in Civil War was the regiment. Regiments were assembled into brigades; brigades into divisions; divisions into corps; and corps into armies.
Capt. R. K. Beecham, a veteran of Gettysburg, discusses the structure of military units in his book, "Gettysburg, the Pivotal Battle of the Civil War," published in 1911:
"The unit of both armies was the regiment, and in that respect the Confederate army had a decided advantage over the Union army. The regimental formation was the same, but the Confederacy adopted a different method of adding recruits.
"The Confederacy, while it lasted, was a military organization, pure and complete; and at the very start their military leaders determined that everything else should bow to the efficiency of their army. Therefore, after the second year of the war they added very few new regiments. ... Instead of making up full regiments entirely of raw and unseasoned men, they divided them up among the old regiments long in the field, wherein every private soldier was as good or better than an officer of a new regiment. Usually, an old regiment of 300 experienced men is worth more in battle than a new regiment of 900. ...
"With the Union army it was different. ... Up to the last year and last month of the war, the State authorities recruited full regiments of green troops and sent them to the front in great unwieldy bodies to fill up the armies, while the old and experienced regiments dwindled into nothingness."
Another result of the Union's policy of enlisting regiments was that whole units vanished when their terms of service expired. The Army of the Potomac lost 5,000 men in May 1863 and 10,000 in June at the beginning of the Gettysburg campaign because their enlistments expired.
"By their system of filling up their old regiments, the Confederates kept them at all times at very nearly their fighting weight, which ... was about 500 men to the regiment; and as
each brigade in both armies contained four or five regiments, it is easy to understand how even a slight difference in the numerical strength of the units created a difference in all the organizations above the unit," Beecham says. These facts present the opportunity of making a comparative estimate of the strength of Lee's army in the Gettysburg campaign that cannot be far from correct. In the Union army we had 51 brigades, and a total strength of infantry of 77,208, or an average of 1,514 men to the brigade. In Lee's army, there were 39 brigades of infantry, which reasonably averaged 1,800 or 2,000 men to the brigade; and if the latter, which was less than several of them numbered, Lee's total infantry strength was about 78,000. But if we estimate the average of Lee's brigades at the former figure of 1,800, it would still give him a total of 70,200 infantry, besides his artillery and cavalry.
In fact, however, there are no means of ascertaining the exact strength of Lee's army. Longstreet gives his estimate at 75,568, which is probably as accurate as any to be obtained from a Confederate source. ..."
FTC With regard to the strength of the Army of the Potomac, there can be no question, Beecham asserts. Maj. Gen. George G. Meade, in his testimony before the Congressional Committee on the Conduct of the War, stated the strength of his army at a little under 100,000 probably 95,000 men.
Newspaper reports of the time aren't much help in deciding this issue. On July 3, 1863, The Sun reported, "The whole army of invaders is not less than 95,000 men; some here [Hagerstown] positively assert there was a trifle over 100,000 crossed the Potomac to their knowledge."
The armies at Gettysburg
These estimates show the approximate strength of the opposing forces at Gettysburg. The Union numbers are reported by Capt. R. K. Beecham, based on the Army of the Potomac's reports of present for duty as of June 30, 1863. Figures for the corps of the Army of Northern Virginia are estimates by Col. Vincent J. Esposito in "The West Point Atlas of American Wars"; cavalry and artillery numbers are taken from "Battles and Leaders of the Civil War":
Unit ..... ..... ..... North ..... South
1st Corps ...... ..... 10,022 .... 20,000
2nd Corps ...... ..... 12,904 .... 21,000
3rd Corps ...... ..... 11,924 .... 21,000
5th Corps ...... ..... 12,509
6th Corps ...... ..... 15,555
11th Corps ..... ..... 9,841
12th Corps ..... ..... 8,589
Reserve Artillery .... 2,546 ..... 4,460
Cavalry Corps ........ 10,809 .... 9,536
Total ................ 94,699 .... 75,996
The views noted above are not the only views on the numbers of soldiers in the opposing armies at Gettysburg. Here are some other authoritative estimates for comparison:
Source .......... .......... North ..... South
Lt. Gen. James Longstreet .. 100,000 ... 75,568
Maj. Gen. George G. Meade .. 100,000 ... 100,000
"Battles and Leaders" ...... 93,500 .... 70,000
Count of Paris ............. 84,000 .... 69,000
"Numbers and Losses" ....... 83,289 .... 75,054
"Civil War Dictionary" ..... 122,000 ... 89,000
Pub Date: 6/25/98