United States Armies and Departments
in the Eastern Theater of the Civil War
December 1861

1861 - 1862 - 1863 - 1864 - 1865
January to March • April • May • June • July • August • September • October • November • December
Army of the Potomac Major General George McClellan   Dept. of Virginia Major General John E. Wool An area 60 miles around Fortress Monroe