Army of the Potomac
Major General George McClellan
The greater part of the Army of the Potomac was operating outside its department in western Maryland after the Battle of Antietam.
Dept. of Virginia
Major General John Dix
An area 60 miles around Fortress Monroe
Major General John E. Wool
New Jersey, Pennsylvania, Delaware, the eastern part of Maryland and the Eastern Shore of Virginia.
Washington D.C. Defenses
Maj. Gen. Nathaniel Banks (to 10/27)
Maj. Gen. Samuel Heintzelman (after 10/27)
District of Columbia, Arlington County in Virginia, and adjacent fortifications