U.S. Army

22nd Army Corps, Department of Washington

Major General Samuel P. Heintzelman

Defences North of the Potomac

Lt. Col. J. A. Haskins

First Brigade

Colonel J. M. Warner (to 5/12)

Colonel W. H. Hayward

Second Brigade

Colonel L. O. Morris

Third Brigade

Colonel A. Piper

Defences South of the Potomac

Col. T. R. Tannatt (until 5/25)

Brig. Gen. G. A. DeRussy

First Brigade

Colonel T. R. Tannatt

Second Brigade

Colonel G. D. Wells (until 5/63)

Col. L. W. Wessells

Third Brigade

Colonel H. L. Abbot

organized 5/12

Abercrombie's Division

Brigadier General J. J. Abercrombie

First Brigade

Col. Francis Fessenden

Second Brigade

Brig. Gen. George J. Stannard

Third Brigade

Colonel George L. Willard (to 5/6)

Brig. Gen. Alexander Hays

Pennsylvania Reserves Division

Brig. Gen. Samuel W. Crawford

First Brigade

Colonel William Sinclair (to 5/29)

Colonel William McCandless

Third Brigade

Colonel J. W. Fisher

Cavalry Division

Major General Julius Shahel

First Brigade

Brig. Gen. J. T. Copeland

Second Brigade

Colonel R. Butler Price

Third Brigade

Colonel O. DeForest

Jewett's Independent Brigade

Colonel A. B. Jewett

23rd Maine Infantry Regiment

to District Alexandria (see below)

39th Massachusetts Infantry Regiment

to District Washington (see below)

14th New Hampshire Infantry Regiment

to District Washington (see below)

10th Vermont Infantry Regiment

11th New York Cavalry, Cos. E, F & I

10th Massachusetts Independent Battery

District of Washington

Brig. Gen. J. H. Martindale

2nd District of Columbia Infantry Regt.

34th Massachusetts Infantry Regiment

from Defences S. Potomac, 3rd Brig. (below)

39th Massachusetts Infantry Regiment

from Jewett's Independent Brig. (see above)

14th New Hampshire Infantry Regiment

from Jewett's Independent Brig. (see above)

27th Pennsylvania Infantry, Co. F

150th Pennsylvania Infantry, Co. K

157th Pennsylvania Infantry (4 cos.)

District of Alexandria

Brig. Gen. John P. Slough

1st District of Columbia Infantry Regt.

23rd Maine Infantry Regiment

153rd New York Infantry Regiment

Pennsylvania Independent Battery H

Second Brigade, Pa. Reserves

Colonel H. G. Sickel

3rd Pennsylvania Reserves Regiment

4th Pennsylvania Reserves Regiment

7th Pennsylvania Reserves Regiment

8th Pennsylvania Reserves Regiment

Light Artillery Camp Camp Berry

Brig. Gen. A. P. Howe

1st New York Artillery, Battery A

12th New York Independent Battery

27th New York Independent Battery

1st West Virginia Artillery, Battery A