The Key Bridge spans the Potomac River, connecting the Georgetown neighborhood in the District of Columbia with the neighborhood of Rosslyn in Arlington County, Virginia.
Key Bridge is Washington's oldest existing road bridge across the Potomac River.

The bridge is an open-spandrel, arched structure oriented in a north-south direction and constructed of reinforced concrete and steel.
Each span consists of three steel arches:  A center arch which is 22 feet (6.7 m) in width, and two outer arches each 11 feet (3.4 m) in width.
To lighten the load on the span arches, the spandrels were filled with additional arches.
Depending on the size of the span, there are either three or four spandrel arches.
Together, the span arch and spandrel arches form a truss.
The piers were decorated with pilasters in the Doric style.

The northern terminus of the bridge is just east of the site of Francis Scott Key's home, which was dismantled in the late 1940s.
A park honoring Key now occupies the site.
The bridge connects with M Street NW, Canal Road NW, and the Whitehurst Freeway (which provides access to K Street NW and 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 southern terminus of the bridge is in the state of Virginia.
Northbound traffic accesses the bridge via North Lynn Street, with southbound traffic exits the bridge via North Fort Myer Drive.
A cloverleaf ramp from southbound George Washington Memorial Parkway connects to northbound North Lynn Street just before the bridge.
Southbound traffic may turn right onto an off-ramp leading to northbound George Washington Memorial Parkway.
The bridge's southbound off-ramp connect with north/west-bound U.S. Route 29.
Traffic wishing to access southbound Interstate 66 (the Custis Memorial Parkway) must do so by traversing local Rosslyn streets.

The bridge originally measured 1,450 feet (440 m) in length, with a roadway 85 feet (26 m) above the average water level.
The original road deck was 70 feet (21 m) wide.
It included two 16-foot (4.9 m) wide traffic lanes, a center lane with streetcar tracks, and two 8-foot (2.4 m) wide sidewalks.
A horizontal, decorative molding ran along the outer edge of the bridge.
 It projected outward by 2 feet (0.61 m).
Atop this cornice was a paneled parapet.
The parapet (or railing) was 4 feet (1.2 m) high and 1 foot (0.30 m) thick.
Between each baluster of the parapet is a 6-foot (1.8 m) recessed panel.
 Atop the parapet were street lights.
These were made of cast iron, were 7-foot-1-inch (2.16 m) tall, and featured a griffin's leg and winged shield at the base.
The light were spaced 40 feet (12 m) apart.

The bridge had five arches when constructed.
The central arch was 208 feet (63 m) long, and the two adjacent arches were 204 feet (62 m) long.
The shoreward arches were each 187 feet (57 m) long.
Separate spans completed the approaches to the bridge.
 The span over the Chesapeake and Ohio Canal in the District of Columbia was either 82 feet (25 m) or 85 feet (26 m) long (sources vary), while the span over K Street NW was 180 feet (55 m) long.
The original approach span on the Virginia side was 152 feet (46 m) long.
The Key Bridge spans the Potomac River, connecting the Georgetown neighborhood in the District of Columbia with the neighborhood of Rosslyn in Arlington County, Virginia. Key Bridge is Washington's oldest existing road bridge across the Potomac River.
The bridge is an open-spandrel, arched structure oriented in a north-south direction and constructed of reinforced concrete and steel. Each span consists of three steel arches:  A center arch which is 22 feet (6.7 m) in width, and two outer arches each 11 feet (3.4 m) in width. To lighten the load on the span arches, the spandrels were filled with additional arches. Depending on the size of the span, there are either three or four spandrel arches. Together, the span arch and spandrel arches form a truss. The piers were decorated with pilasters in the Doric style.
The northern terminus of the bridge is just east of the site of Francis Scott Key's home, which was dismantled in the late 1940s. A park honoring Key now occupies the site. The bridge connects with M Street NW, Canal Road NW, and the Whitehurst Freeway (which provides access to K Street NW and 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 southern terminus of the bridge is in the state of Virginia. Northbound traffic accesses the bridge via North Lynn Street, with southbound traffic exits the bridge via North Fort Myer Drive. A cloverleaf ramp from southbound George Washington Memorial Parkway connects to northbound North Lynn Street just before the bridge. Southbound traffic may turn right onto an off-ramp leading to northbound George Washington Memorial Parkway. The bridge's southbound off-ramp connect with north/west-bound U.S. Route 29. Traffic wishing to access southbound Interstate 66 (the Custis Memorial Parkway) must do so by traversing local Rosslyn streets.
The bridge originally measured 1,450 feet (440 m) in length, with a roadway 85 feet (26 m) above the average water level. The original road deck was 70 feet (21 m) wide. It included two 16-foot (4.9 m) wide traffic lanes, a center lane with streetcar tracks, and two 8-foot (2.4 m) wide sidewalks. A horizontal, decorative molding ran along the outer edge of the bridge.  It projected outward by 2 feet (0.61 m). Atop this cornice was a paneled parapet. The parapet (or railing) was 4 feet (1.2 m) high and 1 foot (0.30 m) thick. Between each baluster of the parapet is a 6-foot (1.8 m) recessed panel.  Atop the parapet were street lights. These were made of cast iron, were 7-foot-1-inch (2.16 m) tall, and featured a griffin's leg and winged shield at the base. The light were spaced 40 feet (12 m) apart.
The bridge had five arches when constructed. The central arch was 208 feet (63 m) long, and the two adjacent arches were 204 feet (62 m) long. The shoreward arches were each 187 feet (57 m) long. Separate spans completed the approaches to the bridge.  The span over the Chesapeake and Ohio Canal in the District of Columbia was either 82 feet (25 m) or 85 feet (26 m) long (sources vary), while the span over K Street NW was 180 feet (55 m) long. The original approach span on the Virginia side was 152 feet (46 m) long.
Key Bridge (Washington, D.C.)