The valley of the South Branch of the Potomac River was a Civil War middle ground, situated between the all-important middle Shenandoah Valley and the Upper Potomac region. It offered vital coal resources and access to the B&O Railroad infrastructure centered around Cumberland, Maryland. Federal or Confederate troops occupied this hill and its surrounding area beginning at least as early as August 1861, and were on the ground for at least part of every year of the war.
Backstory and Context
Federal forces time and again tried to use this strategic point as a choke hold against raids on the B&O to the north, and as a jumping-off point for their own raids further south. The Fort as it exists today was constructed from August to December of 1863 by troops under the command of Colonel James A. Mulligan from Chicago, IL. Infantry, cavalry and artillery from West Virginia, Pennsylvania, Maryland and Illinois carried out the labor. Known locally as Fort Hill, Fort Mulligan was to serve as protection for the South Branch Valley from Confederate forces and also as an auxiliary depot to supply numerous Union troops on their expeditions.
Fort Mulligan, American Battlefield Trust. Accessed September 29th 2020. https://www.battlefields.org/learn/civil-war/battles/fort-mulligan.
West Virginia's Sesquicentennial Highway Historical Marker Program. Accessed September 21, 2020. http://www.wvculture.org/history/markers/sesqui/fortmulligan.html.