Fortifications

Fort Williams (1861-1865) - A Union Civil War Fort first established in 1861 in the present day City of Alexandria, Virginia. Named Fort Williams after Brigadier General Thomas R. Williams, U.S. Volunteers, who was killed at Baton Rouge 5 Aug 1862.  The fort was a large earthworks with a perimeter of 250 yards and emplacements for 13 guns.

Established in 1861 on Cooper's Hill between Fort Worth and Fort Ellsworth on the site of Confederate General Samuel Cooper's  home known as "Cameron".  His home was destroyed to build the fort.  ( Source - Fortwiki )