 Between its endpoints, US 421 has lengthy concurrencies with US 23 and US 58 during its course through Bristol, Weber City, Gate City, Duffield, and Pennington Gap in Southwest Virginia.US 421 enters Virginia at State Street, which follows the boundary between Bristol, Virginia, and Bristol, Tennessee, and heads north on Commonwealth Avenue, which also carries US 11E, US 19, and SR 381.Prior to spring 2011, US 421 followed a more convoluted routing on Martin Luther King Jr. Boulevard, Cumberland Street, Piedmont Avenue, and Goode Street (all but MLK also being U.S. Route 11-19 Truck).