U.S. Route 1 (US 1) is a major north–south U.S. Highway, extending from the Florida Keys in the south to the Canadian border in the north. In the U.S. state of Pennsylvania, US 1 runs for 81 miles (130 km) from the Maryland state line near Oxford to the New Jersey state line near Trenton, through the southeastern portion of the state. The route runs southwest to northeast, and serves as a major arterial road for many of the suburbs in the Delaware Valley area. South of Philadelphia, the road mostly follows the alignment of the old Baltimore Pike. Within Philadelphia, it mostly follows Roosevelt Boulevard.