Peninsula campaign Union order of battle

The following Union Army units and commanders were the initial structure on April 4, 1862 of the Union Department of the Potomac during the Peninsula campaign of the American Civil War. This list includes units deployed to the Virginia Peninsula, and those that remained in the Washington area. The Confederate order of battle is listed separately.
Army of the Potomac.
The following units were the initial organization of the Army of the Potomac on the peninsula.
MG George B. McClellan, Commanding
"Headquarters and Body Guard"
"Provost Guard"
Staff.
Col Randolph B. Marcy, Chief of Staff
Maj Granville O. Haller, Commandant of General Headquarters
II Corps.
BG Edwin Sumner, Commanding
<br> Ltc Joseph H. Taylor, Adjutant
III Corps.
BG Samuel P. Heintzelman, Commanding
<br>  Cpt Chauncey McKeever, Chief of Staff
IV Corps.
BG Erasmus D. Keyes, Commanding
<br>  Ltc Charles C. Suydam
Other Troops from the Department of the Potomac.
The following troops were part of the Department of the Potomac in March and April 1861, but were detached to maintain defense of the Potomac River line.
I Corps.
MG Irvin McDowell, Commanding
<br>  Ltc Edmund Schriver, Chief of Staff
"Unattached cavalry"
"Sharpshooters"
V Corps.
MG Nathaniel P. Banks, Commanding
<br>  Cpt Louis H. Pelouze, Acting Assistant Adjutant General
"Unattached Infantry"
District of Washington.
BG James S. Wadsworth, Commanding
<br>"Railroad Guards"
<br>  Col Dixon S. Miles
Troops Around Baltimore.
MG John A. Dix, Commanding
<br>  Maj Daniel Tompkins Van Buren, Chief of Staff and Acting Assistant Adjutant General
Department of Virginia.
MG John E. Wool, Commanding
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References.
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