Langdon, Washington, D.C.

Langdon, or Langdon Park, is a neighborhood near the U.S. National Arboretum in Northeast Washington, D.C. Langdon is roughly bounded by New York Avenue NE to the south, Montana Avenue to the west, Bladensburg Road to the east, Rhode Island Avenue NE to the northwest, and South Dakota Avenue to the northeast. The neighborhood of Brentwood is to the east, Woodridge is to the west, Brookland to the north.

Langdon is predominantly a residential neighborhood, with a commercial/industrial strip west of the railroad tracks that run northeast/southwest through the neighborhood. A number of prominent go-go clubs are located on Bladensburg Road in Langdon.

Langdon is home of the 9/11 Memorial Grove, a memorial at the intersection of 18th and Hamlin Streets NE.

Langdon Park's public swimming pool was chosen as the first venue where Mayor Williams started the tradition of launching "DC's Summer Fun" by cannonball-diving into a chosen pool. Mayor Fenty broke the tradition and instead just blew a whistle.