Marion is an unincorporated community and census-designated place (CDP) in Franklin County, Pennsylvania, United States. As of the 2010 census the population was 953.
It lies along U.S. Route 11 6 miles (10 km) south of Chambersburg and 5 miles (8 km) north of Greencastle. Interstate 81 passes along the eastern edge of the community, with access from Exit 10 (Pennsylvania Route 914). I-81 leads northeast 37 miles (60 km) to Carlisle and south 17 miles (27 km) to Hagerstown, Maryland.
Marion was originally called Independence, and under the latter name was laid out in about 1810. A post office called Marion has been in operation since 1833. The present name is after Francis Marion, army officer during the American Revolutionary War, known as the Swamp Fox.