Third Corps

Major General Irvin McDowell (until 9/5)

Brigadier General J. B. Ricketts (9/5 - 9/6)

Major General Joseph Hooker (after 9/6)

Discontinued and merged into the Army of the Potomac as the First Army Corps, September 12, 1862

First Division

Bde. Gen. Abner Doubleday

First Brigade

Colonel T. Sullivan

Colonel J. W. Hoffman

Bde. Gen. Marsena R. Patrick

Bde. Gen. John Gibbon

Brigadier General John B. Ricketts

First Brigade

Bde. Gen. A. Duryea

Colonel W. H. Christian

Colonel J. W. Stiles (until 9/2)

Bde. Gen. George Hartsuff (after 9/2)

Colonel Joseph Thoburn

Brigadier General John F. Reynolds

First Brigade

Bde. Gen. Truman Seymour

Bde. Gen. George G. Meade

Lt. Colonel Robert Andrson (9/1)

Colonel T. F. Gallagher (after 9/1)