U.S. Army

Army of the Potomac

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 was transferred to the Department of Virginia, while its other division was transferred to the 6th Corps. The three corps of the Pope's Army of Virginia were merged into the Army of the Potomac as the First, Eleventh and Twelfth Corps and thousands of newly recruited men were added, sometimes in entire brigades of raw and inexperienced men. The new organization was barely in place before the army embarked on the campaign that culminated in the Battle of Antietam, the bloodiest single day in the army's - and America's - history.

Headquarters

First Army Corps

Major General Joseph Hooker (w 9/17)
Bde. Gen. George Meade (9/17-9/29)

Bde. Gen. John F. Reynolds (after 9/29)

recreated from Army of Virginia, 3rd Corps

1st Division

Bde. Gen. Rufus King

Bde. Gen. J.P. Hatch (9/14)

Bde. Gen. Abner Doubleday (after 9/14)

2nd Division

Brigadier General J. B. Ricketts

3rd Division

Bde. Gen. George Meade (except 9/17-9/29)
Bde. Gen. Truman Seymour (9/17-9/29)

Second Army Corps

Major General Edwin V. Sumner

1st Division

Bde. Gen. Israel B. Richardson (mw 9/17)
Bde. Gen. John C. Caldwell (9/17)
Bde. Gen. Winfield S. Hancock (after 9/17)

2nd Division

Bde. Gen. John Sedgwick (w 9/17)
Bde. Gen. Oliver O. Howard

3rd Division

Brigadier General William H. French

created 9/10

Third Army Corps

Major General Samuel P. Heintzelman

1st Division

Bde. Gen. Philip Kearney (k 9/1)
Bde. Gen. David B. Birney (9/1-9/13)
Bde. Gen. George Stoneman (after 9/13)

2nd Division

Bde. Gen. Joseph Hooker (to 9/5)
Bde. Gen. Daniel Sickles

Fourth Army Corps

Brigadier General Erasmus Keyes

1st Division

Bde. Gen. Darius N. Couch

transferred to 6th Army Corps 9/26 (see below)

2nd Division

Bde. Gen. J. J. Peck

transferred to Dept. of Virginia 9/26

Fifth Army Corps

Brigadier General Fitz John Porter

1st Division

Bde. Gen. George W. Morrell

2nd Division

Bde. Gen. George Sykes

3rd Division

Bde. Gen. Aendrew A. Humphreys

recreated 9/12

Sixth Army Corps

Major General William B. Franklin

1st Division

Bde. Gen. Hennry W, Slocum

2nd Division

Bde. Gen. William F. Smith

3rd Division

Bde. Gen. Darius N. Couch

transferred from 4th Corps 9/26 (see above)

Ninth Army Corps

Major General Ambrose Burnside (to 9/3)
Major General Jesse Reno (9/3 - mw 9/14) Bde. Gen. Jacob D. Cox (after 9/14)

1st Division

Bde. Gen. Isreal I. Stevens (k 9/1)
Col. B. C. Christ (9/1-9/8)
Bde. Gen. Orlando Wilcox (after 9/8)

2nd Division

Major General Jesse Reno (to 9/3)
Bde. Gen. Samuel D. Sturgis (after 9/3)

3rd Division

Major Gen. J. G. Parke (to 9/3 & after 9/17)
Bde. Gen. I. P. Rodman (9/3 - mw 9/17)

Kanawha Division

Brigadier General J. D. Cox

attached September from West Virginia

Eleventh Army Corps

Major General Franz Sigel

created 9/12 from Army of Virginia, 1st Corps

1st Division

Bde. Gen. Julius H. Stahel

2nd Division

Bde. Gen. Adolph Von Steinwehr

3rd Division

Bde. Gen. Carl Schurz

Twelfth Army Corps

Major Gen. J. F. K. Mansfield (mw 9/17)

Bde. Gen. A. S. Williams

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

1st Division

Bde. Gen. Alpheus Williams (until 9/17)

Bde. Gen. Samuel W. Crawford (w 9/17)

Bde. Gen. George Gordon (after 9/17)

2nd Division

Brigadier General George Greene

Cavalry Division (to Sept.)

Brigadier General George Stoneman

1st Brigade

Colonel W. W. Averill

2nd Brigade

Bde. Gen. Alfred Pleasonton

Cavalry Division (after Sept.)

Brigadier General A. Pleasonton

1st Brigade

Major C. Whiting

2nd Brigade

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