The Greenbrier River Trail is West Virginia's Millennium Legacy Trail, one of 52 such trails nationwide. It is perhaps the best-known and most used rail-trail in the state and is managed by West Virginia's state park system. The 78-mile trail follows the old Greenbrier Division of the Chesapeake & Ohio (C&O) Railway along the Greenbrier River, traveling from Cass in Pocahontas County to Caldwell, near Lewisburg, by way of Seneca State Forest, Marlinton, Watoga State Park, and Calvin Price State Forest. Many bicyclists begin their adventure at Cass and end in Caldwell, taking two or three days to complete the journey. In June 2021, the trail was added to the National Trails System, a network of more than 1,300 recreation trails across the United States.

Built to haul the region's vast timber resources to market, the Greenbrier Division of the C&O was active from 1900 to 1978. Mark A. Hankins, of Lewisburg, whose grandfather and father had planned the Greenbrier Division as engineers, was instrumental in acquiring the right of way for the trail. With access from many points in Greenbrier and Pocahontas counties, the visitor doesn't have to ride or walk the entire trail to enjoy the scenery, wildflowers, and animals that share the river and trail. Trail maps showing the location of facilities and camping areas are available from visitor centers in Pocahontas and Greenbrier counties. The Greenbrier River Trail, which was added to the State Park system in 1980, includes 950 acres.