High Quality Content by WIKIPEDIA articles! Interstate 81 (I-81) is an 846-mile (1,362 km) long highway. In the U.S. state of Virginia, I-81 runs for 324.92 miles (522.91 km), making it longer in Virginia than in any other state. It stretches from the Tennessee state line near Bristol to the West Virginia state line near Winchester. For most of its length, U.S. Route 11 parallels I-81.