United States Army > Army of the Potomac

September 1862 • to October >

Commanded by
Major General Joseph Hooker (wounded September 17)
Brigadier General G. Meade 
(September 17 – 29)
Brigadier General John F. Reynolds

On September 12, 1862 the Third Corps of the Army of Virginia was redesigned the First Corps of the Army of the Potomac. The First Corps was engaged in both the Battle of South Mountain on September 14 and the Battle of Antietam on September 19, suffering heavy casualties.

Headquarters Escort
2nd New York Cavalry, Companies A, B, I & K Captain John E. Naylor
First Division Brigadier General Rufus King (to 9/14)
Brigadier General John P. Hatch (w 9/14)
Brigadier General Abner Doubleday
1st Brigade Brig. Gen. J. P. Hatch (^ 9/14)
Colonel Walter Phelps, Jr.
2nd Brigade Brig. Gen. A. Doubleday (^ 9/14)
Colonel W. P. Wainwright (9/14 – 9/17)
Colonel J. W. Hoffman
3rd Brigade Brig. Gen. Marsena Patrick
4th Brigade Brig. Gen. John Gibbon
Second Division Brigadier General John B. Ricketts (to 9/17)
1st Brigade Brig. Gen. Abram Duryea
2nd Brigade Colonel W. H. Christian (9/12 – 9/18)
Colonel Peter Lyle
3rd Brigade Brig. Gen. G. L. Hartsuff (w 9/17)
Colonel R. Coulter
Third Division Brigadier General G. Meade (except 9/17-9/29)
Brigadier General T. Seymour (9/17-9/29)
1st Brigade Brig. Gen. Truman Seymour (except 9/12 – 9/17)
Colonel R. B. Roberts (9/17-9/29)
2nd Brigade Colonel A. L. Magilton
3rd Brigade Colonel T. F. Gallagher (to 9/14)
Lt. Colonel R. Anderson (9/14)
Colonel J. W. Fisher