Department of the East (Pre-war)
Major General John E. Wool
All of the United States east of the Mississippi not in other departments.
Dept. of Washington (est. 4/9)
Lt. Colonel Charles F. Smith (4/9-4/28)
Colonel Joseph K. F. Mansfield (after 4/28)
The District of Columbia (including Alexandria County, Va.), and Maryland as far as Bladensburg.
Dept. of Pennsylvania (est. 4/19)
Major General Robert Patterson
Pennsylvania, Delaware, and Maryland not in the Depts. of Washington and Annapolis.
Dept. of Annapolis (est. 4/27)
Brigadier General Benjamin F. Butler
Maryland between Annapolis, Baltimore and Washington.