U.S. Army - Army of the Potomac - First Army Corps

First Division

Brigadier General Rufus King (until 9/14)

Brigadier General J. P. Hatch (w 9/14)

Brigadier General Abner Doubleday(after 9/14)

Recreated from the Army of Virginia, 3rd Army Corps on September 12, 1862

First Brigade

Brigadier General J. P. Hatch (9/12 - 9/14)
Colonel Walter Phelps, Jr. (after 9/14)

22nd New York Infantry Regiment

Colonel Walter Phelps (until 9/14)

Lt. Colonel John McKie Jr. (after 9/14)

24th New York Infantry Regiment

Captain John D. O'Brien (w 9/17)

Major Robert Oliver (after 9/29)

30th New York Infantry Regiment

Colonel William M. Searing

14th New York State Militia (84 NY)

Major William H. deBevoise

2nd United States Sharpshooters

Colonel Henry Post (w 9/17)

Second Brigade

Brigadier General Abner Doubleday (9/12 - 9/14)

Colonel W. P. Wainwright (w 9/14)

Lt. Colonel J. W. Hoffman (after 9/14)

7th Indiana Infantry Regiment

Major Ira G. Grover

76th New York Infantry Regiment

Colonel William P. Wainwright (until 9/14)

Lieutenant Chauncey Crandell (9/14)

Captain John W. Young (after 9/14)

95th New York Infantry Regiment

Major Edward Pye

56th Pennsylvania Infantry Regiment

Lt. Colonel John W. Hoffman (until 9/14)

Captain Frederick Williams (after 9/14)

Third Brigade

Brigadier General Marsena R. Patrick

21st New York Infantry Regiment

Colonel William F. Rogers

23rd New York Infantry Regiment

Colonel Henry C. Hoffman

35th New York Infantry Regiment

Colonel Newton B. Lord

20th New York State Militia (80th N.Y)

Lt. Colonel Theodore B. Gates

Fourth Brigade

Brigadier General John Gibbon

19th Indiana Infantry Regiment

Colonel Solomon Meredith (until 9/16)

Lt. Colonel Alois O. Bachmann (9/16-k 9/17)

Captain William W. Dudley (after 9/17)

2nd Wisconsin Infantry Regiment

Colonel Lucius Fairchild

6th Wisconsin Infantry Regiment

Lt. Colonel Edward S. Bragg (w 9/14)

Major Rufus R. Dawes (after 9/14)

7th Wisconsin Infantry Regiment

Captain John B. Callis

Artillery

Captain John Albert Monroe

1st New Hampshire Battery

Lieutenant Frederick M. Edgell

Battery D, 1st Rhode Island Artillery

Captain John Albert Monroe

Battery L, 1st New York Artillery

Captain John A. Reynolds

Battery B, 4th United States Artillery

Captain Joseph Campbell (w 9/17)

Lieutenant James Stewart