The United States Army in the Eastern Theater

< to April • May 1861 • to June >

Commanded by Major General Winfield Scott

Department of Washington 
Colonel Joseph K. F. Mansfield 

Department of Pennsylvania
Major General Robert Patterson

Department of Annapolis 
Brigadier General Benjamin F. Butler (until 5/22; Major General on 5/16)
Major General George Cadwallader

Dept. of Virginia (established 5/22)
Major General Benjamin F. Butler
Consisting of an area 60 miles around Fortress Monroe

Dept. of Northeastern Virginia (established 5/27)
Brigadier General Irvin McDowell
Consisting of Virginia east of the Allegheny Mountains and north of the James River, except the Department of Virginia.

Department of the East (Pre-war)
Major General John E. Wool

Dept. of Washington
Dept. of Pennsylvania
Dept. of Annapolis

Dept. of Virginia

Dept. of N.E. Virginia