State Route 55 is a primary state highway in the U.S. state of Virginia. Known for most of its length as John Marshall Highway, the state highway runs 64.71 miles (104.14 km) from the West Virginia state line, where the highway continues as West Virginia Route 55, east to U.S. Route 29 in Gainesville. West of its interchange with Interstate 81 (I-81) in Strasburg, SR 55 runs concurrently with the easternmost portion of US 48 as part of Corridor H. East of Front Royal, the state highway serves as the local complement of I-66 as it passes through the towns of Marshall, The Plains, and Haymarket.

U.S. Route 29 (US 29) is a major north–south route in the commonwealth of Virginia. It covers 248.0 miles (399.1 km) from the North Carolina border at the city of Danville to the Key Bridge in Washington DC. US 29 roughly bisects Virginia into eastern and western halves and, along with Interstate 81 (I-81) and US 11 in western Virginia and I-85/I-95 as well as US 1 farther east, provides one of the major north–south routes through the commonwealth.