U.S. Route 15 (US 15) is a 791.71 mi (1,274.13 km)-long United States highway, running from Walterboro, South Carolina, north to Painted Post, New York. In Pennsylvania, the highway runs for 194.89 miles (313.65 km), from the Maryland state line just south of Gettysburg, north to the New York state line near Lawrenceville.