The BMT Canarsie Line is a rapid transit line of the B Division of the New York City Subway system, named after its terminus in the Canarsie neighborhood of Brooklyn. It is served by the L train at all times, which is shown in medium gray on the New York City Subway map and on station signs.

Canarsie is a mostly residential neighborhood in the southeastern portion of Brooklyn, New York City. Canarsie is bordered on the east by Fresh Creek Basin, East 108th Street, and Louisiana Avenue; on the north by Linden Boulevard; on the west by Ralph Avenue; on the southwest by Paerdegat Basin; and on the south by Jamaica Bay. It is adjacent to the neighborhoods of East Flatbush to the west, Flatlands and Bergen Beach to the southwest, Starrett City to the east, East New York to the northeast, and Brownsville to the north.