The Francis Scott Key Bridge, or, more commonly, the Key Bridge, is a reinforced concrete arch bridge conveying U.S. Route 29 traffic across the Potomac River between the Rosslyn section of Arlington County, Virginia, and the Georgetown section of Washington, D.C. Nathan C. Wyeth was the architect for Key Bridge. It was built by the United States Army Corps of Engineers between 1917 and 1923 and was named after Francis Scott Key, author of the Star Spangled Banner. The northern terminus of the bridge is just east of the site of Key's Georgetown home, which was later demolished; near that site, there is now a community park honoring Key.
At its southern (Virginia) terminus, the Key Bridge connects with North Lynn Street and, via that street, with Wilson Boulevard, the George Washington Parkway, Lee Highway (U.S. Route 29), Interstate 66, and State Route 110. At its northern (D.C.) terminus, the bridge connects with M Street, N.W., Canal Road, N.W., and the Whitehurst Freeway, which provides access to K Street downtown. The northbound span has an exit ramp to the eastbound Whitehurst Freeway; however, traffic from the westbound Whitehurst Freeway to the southbound span must use M Street.
The Key Bridge is part of the National Highway System.
Because of the considerable traffic congestion that can develop on the bridge, some locals have jokingly referred to it as the "Car Strangled Spanner," a play on the title of Francis Scott Key's most famous song. The term is relatively rare, and has also been applied to bridges in other cities.
The Key Bridge replaced the Aqueduct Bridge. The Aqueduct Bridge was originally built to carry the Chesapeake and Ohio Canal across the Potomac to connect with the Alexandria Canal. After the Alexandria Canal was abandoned, the bridge was converted into a roadway. The Washington abutment still survives and is located west of the Key Bridge. One pier remains and is located in the river near the Virginia shore.