United States Army

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Commanded by Major General George B. McClellan

In September of 1862 most of the Army of the Potomac returned from the Virginia Peninsula to the Washington area. One division of the Fourth Corps was left behind and transferred to the Department of Virginia, while its other division was transferred to the 6th Corps. The three corps of the Pope’s badly defeated Army of Virginia merged into the Army of the Potomac as its First, Eleventh and Twelfth Corps. Thousands of new recruits joined, sometimes in entire brigades of raw and inexperienced men. The ink on the orders of new organization was not even dry before the army marched out of Washington on the campaign that culminated in the Battle of Antietam, the bloodiest single day in Civil War history.

Headquarters & Staff

First Corps

Major General Joseph Hooker (w 9/17)
Brig. Gen. George Meade (to 9/29)
Brig. Gen. John F. Reynolds
1st Division Brig. Gen. Rufus King
Brig. Gen. J.P. Hatch (w 9/14)
Brig. Gen. Abner Doubleday
recreated from
Army of Virginia, 3rd Corps
2nd Division Brigadier General J. B. Ricketts
3rd Division Brig. Gen. George Meade (to 9/17)
Brig. Gen. Truman Seymour (to 9/29)
Brig. Gen. George Meade

Second Corps

Major General Edwin V. Sumner
1st Division Brig. Gen. Israel Richardson (mw 9/17)
Brig. Gen. John C. Caldwell (9/17)
Brig. Gen. Winfield S. Hancock
2nd Division Brig. Gen. John Sedgwick (w 9/17)
Brig. Gen. Oliver O. Howard
3rd Division Brigadier General William H. French created 9/10

Third Corps

Major General Samuel P. Heintzelman
1st Division Brig. Gen. Philip Kearney (k 9/1)
Brig. Gen. David B. Birney (to 9/13)
Brig. Gen. George Stoneman
2nd Division Brig. Gen. Joseph Hooker (to 9/5)
Brig. Gen. Daniel Sickles

Fourth Corps

Brigadier General Erasmus Keyes
1st Division Brig. Gen. Darius N. Couch to 6th Corps 9/26 (below)
2nd Division Brig. Gen. J. J. Peck to Dept. of Virginia 9/26

Fifth Corps

Major General Fitz John Porter
1st Division Brig. Gen. George W. Morrell
2nd Division Brig. Gen. George Sykes
3rd Division Brig. Gen. Andrew A. Humphreys recreated 9/12

Sixth Corps

Major General William B. Franklin
1st Division Brig. Gen. Hennry W. Slocum
2nd Division Brig. Gen. William F. Smith
3rd Division Brig. Gen. Darius N. Couch from 4th Corps 9/26 (above)

Ninth Corps

Major General Ambrose Burnside (to 9/3)
Major General Jesse Reno (9/3 – mw 9/14)
Brig. Gen. Jacob D. Cox
1st Division Bde. Gen. Isreal I. Stevens (k 9/1)
Col. B. C. Christ (to 9/8)
Bde. Gen. Orlando Wilcox
2nd Division Major General Jesse Reno (to 9/3)
Brig. Gen. Samuel D. Sturgis
3rd Division Major Gen. J. G. Parke (to 9/3)
Brig. Gen. I. P. Rodman (mw 9/17)
Major Gen. J. G. Parke
Kanawha Division Brigadier General J. D. Cox (^ 9/14)
Colonel Eliakim Scammon
from Dept. West Virginia

Eleventh Corps

Major General Franz Sigel
1st Division Bde. Gen. Julius H. Stahel created 9/12 from
Army of Virginia, 1st Corps
2nd Division Bde. Gen. Adolph Von Steinwehr
3rd Division Brig. Gen. Carl Schurz

Twelfth Corps

Major Gen. J. F. K. Mansfield (mw 9/17)
Brigadier General Alpheus S. Williams
1st Division Brig. Gen. Alpheus Williams (to 9/17)
Brig. Gen. Samuel W. Crawford (w 9/17)
Brig. Gen. George Gordon

created 9/12 from
Army of Virginia, 2nd Corps

2nd Division Brigadier General George Greene

Cavalry Division 

Brigadier General George Stoneman (to 9/13)
Brigadier General Alfred Pleasonton
1st Brigade Colonel W. W. Averill  (to 9/13)
Major C. Whiting
2nd Brigade Brig. Gen. Alfred Pleasonton (to 9/13)
Colonel John F. Farnsworth
3rd Brigade Colonel Richard H. Rush
4th Brigade Colonel A. T. McReynolds
5th Brigade Colonel Benjamin F. Davis
Bayard’s Brigade Brigadier General G. D. Bayard