Formerly Fort Pennsylvania, Fort Reno was established on April 1, 1863. Fort Pennsylvania hospital was organized as part of the Fort Hospitals of the Defenses of Washington, North of the Potomac, around March 1862 by Brigadier General James S. Wadsworth.

Fort Pennsylvania/Reno served as a post hospital for the garrisons, forts and redoubts of the 2nd Brigade, and then the 1st Brigade upon the brigade's redefinition in July 1864. The forts, garrisons and redoubts of the 2nd/1st Brigade were: Reno (Head Quarters), Kearney, DeRussy, Sumner, Simmons, Mansfield, Bayard, Gaines.