Fortifications

Fort Gaines (1861-1865) - A Union U.S. Civil War Fort established in 1861 in Northwest Washington DC. Named Fort Gaines in GO 18, 30 Sep 1861, possibly after Brigadier General Edmund Pendleton Gaines, War of 1812 Veteran. 

Established in August 1861 as a earthen fort with a perimeter of 171 yards and emplacements for six guns.

Location:  Near Ward Circle on the grounds of American University in Northwest Washington DC.  ( Source - Fortwiki )