Connecticut Avenue is a major thoroughfare in the Northwest quadrant of Washington, D.C., and suburban Montgomery County, Maryland. It is one of the diagonal avenues radiating from the White House, and the segment south of Florida Avenue was one of the original streets in Pierre Charles L'Enfant's plan for Washington.
Connecticut Avenue begins just north of the White House at Lafayette Square. It is interrupted by Farragut Square. North of Farragut Square and K Street, Connecticut Avenue is one of the major streets in downtown Washington, with high-end restaurants, historical buildings such as Sedgwick Gardens, hotels, and shopping. As Connecticut Avenue approaches the Dupont Circle neighborhood, it splits at N Street into a through roadway and service roadways. The through roadway tunnels under Dupont Circle, while the service roadways intersect the outer roadway of the circle. Just north of the circle, the service roadways are known for their many gay-oriented businesses, of which the most famous is Lambda Rising. The through roadway and service roadways rejoin at R Street. Originally, there was no tunnel, and all vehicular traffic on Connecticut Avenue went through the circle. The tunnel was built in 1949. After crossing Florida Avenue near the Hilton Washington hotel, Connecticut Avenue narrows and winds between the Kalorama neighborhoods. The avenue then crosses Rock Creek Park on the William Howard Taft Bridge and goes through upper Northwest Washington, D.C., including the Woodley Park, Cleveland Park, Forest Hills, and Chevy Chase, D.C. neighborhoods. Between Woodley Park and Cleveland Park, Connecticut Avenue is carried over a deep valley on another bridge. Numerous older, Art Decohigh-rise apartment buildings line the 3000 block, with slightly newer apartment buildings in the 4000 and 5000 blocks. The National Zoological Park is located along Connecticut Avenue, halfway between the Woodley Park-Zoo/Adams Morgan and Cleveland Park Metro stations. Also located along this stretch of Connecticut Avenue is a major operational center of Intelsat, as are the landmark Wardman Park Marriott Hotel, the city's largest, and the Omni Shoreham Hotel. This section is also a major commuter route and has reversible lanes along most of its length which operate during the morning and evening rush hours. It connects with the Rock Creek and Potomac Parkway via 24th Street. Mid-century era high-rise apartments line the avenue, with elegant, older detached homes on shady side streets.