U.S. Route 15 (US 15) is a 791.71 mi (1,274.13 km)-long United States highway, designated along South Carolina, North Carolina, Virginia, Maryland, Pennsylvania, and New York. The route is signed north–south, from U.S. Route 17 Alternate in Walterboro, South Carolina to Interstate 86 and NY 17 in Painted Post, New York.US 15 is one of the original United States Highways from 1926.