Lee had felt that the corps of his current army
organization of two corps was too large for one commander.
Each corps contained about 30,000 men and could not be kept under their
commander’s eye in battle. With the loss of Jackson at the battle of Chancellorsville,
April 26 to May 6, Lee decided to reorganize the army from a two corps four
division arrangement to a new arrangement of three Corps with three divisions
each. The new ninth division was
created from two brigades of A.P. Hill’s division and two new brigades from
Richmond and North Carolina. With
Special Orders No. 146 of May 30th 1863, the third corps was formed.
Each Corps included three battalions of Artillery with a corps reserve of two Battalions.
Major General J.E.B. Stuart commanded the Cavalry Division. Composed of the following six brigades.
Hampton's Brigade, Fitz Lee’s Brigade, W.H.F. Lee’s Brigade, W.E. Jones’ Brigade, B.H. Robertson’s Brigade, A.G. Jenkins’ Brigade
At this time the number of effective bayonets in the ANV was around 75,000 including the artillery of about 275 guns. The cavalry accounted for 12,000 to 15,000 men. The Total force available to the ANV was close to 90,000. This number varied greatly when you consider present for duty and absent returns.
The reorganization was not without its drawbacks and
shortcomings. Two of the corps
commander and nine division commanders were new to the job.
Six of the 37 brigades were under new commanders and another 6 under
Colonels not ready for promotion.
One month after Chancellorsville and four days after this reorganization the Army was put on the march. The Gettysburg campaign was put in motion.
Unit Organization comparison
Union corps were smaller then the CSA Corps because Union brigades and therefore divisions
were smaller. Typically a USA brigade had
between 800 and 1,700 men. A CSA brigade had between 1,400 and 2,000
men. A USA division had between 3,000 to 7,000 and a CSA division between
6,000 to 14,000. A USA corps had between 12,000 and 14,000 and a CSA corps
between 24,000 and 28,000.
Sources:
The Civil War narrative; Shelby Foote
Harper's Pictorial History of the Civil War; AH Guernsey & HM Alden
The US Army War College Guide to the Battle of Gettysburg