Fort Loudon is an unincorporated community and census-designated place (CDP) in Peters Township, Franklin County, Pennsylvania, United States.

[4] The community is named after the colonial Fort Loudoun, built in 1756 during the French and Indian War.

[6] Fort Loudon is located in western Franklin County in the valley of the West Branch Conococheague Creek, with Cove Mountain to the west, Blue Mountain to the north, and Parnell Knob to the east.

U.S. Route 30, the Lincoln Highway, passes through the community, leading west 8 miles (13 km) to McConnellsburg and east 13 miles (21 km) to Chambersburg, the Franklin County seat.

According to the U.S. Census Bureau, the Fort Loudon CDP has an area of 4.2 square miles (11.0 km2), all land.