U.S. Route 1 and Interstate 395 enter the District of Columbia from Virginia on the 14th Street Bridge. Route 1 traffic exits Route 395 from the left to 14th Street, S.W. After 14th Street crosses the National Mall, Route 1 turns right onto Constitution Avenue. It then turns left onto 6th Street, N.W., and then right onto Rhode Island Avenue. Route 1 continues on Rhode Island Avenue through Northeast Washington and into Maryland.
U.S. Route 1 enters the District of Columbia from Maryland on Rhode Island Avenue. Route 1 turns left onto 6th Street, N.W., then right onto L Street, N.W., and then left onto 9th Street, N.W. It enters the Ninth Street Tunnel and joins Interstate 395, which it follows into Virginia.