Rhode Island Avenue is a diagonal avenue in the Northwest and Northeast quadrants of Washington, D.C. and the capital's inner suburbs in Prince George's County, Maryland. Paralleling New York Avenue, Rhode Island Avenue was one of the original streets in Pierre L'Enfant's plan for the capital. Today it is a major commuter route, carrying U.S. Route 1 traffic into the city from Prince George's County.

The western terminus of Rhode Island Avenue is in downtown Washington, at an intersection with Connecticut Avenue and M Street, N.W. The Cathedral of St. Matthew the Apostle is on Rhode Island Avenue, just east of that intersection. Just east of the cathedral, at Scott Circle, Rhode Island Avenue intersects Massachusetts Avenue and 16th Street, N.W. N Street stops short of meeting the circle from either direction, but is instead connected to Rhode Island and Massachusetts avenues through two short streets, Corregidor Street and Bataan Street. From Scott Circle, Rhode Island Avenue continues eastward to the Logan Circle neighborhood. At the traffic circle of the same name, Rhode Island Avenue intersects Vermont Avenue, 13th Street, and P Street, N.W.

East of Logan Circle, Rhode Island passes through primarily residential neighborhoods such as Bloomingdale, Shaw and Brentwood. Rhode Island Avenue is U.S. Route 29 between 7th and 11th streets, N.W., and U.S. Route 1 east of 6th Street, N.W. In Northeast Washington, Rhode Island Avenue is served by the Rhode Island Ave-Brentwood station on the Red Line and the Shaw-Howard University station on the Green Line of the Washington Metro.

In 1926, Rhode Island Avenue was extended from the District line through Mount Rainier, Brentwood, and North Brentwood.^[1]

In downtown Hyattsville, Rhode Island Avenue merges into Baltimore Avenue (U.S. Highway 1 Alternate). U.S. Highway 1 traffic continues north on Baltimore Avenue. Discontinuous segments of Rhode Island Avenue exist in Riverdale Park, College Park, and Beltsville.