[1] The underpass runs underneath the Battery, connecting the West Side Highway to the South Street Viaduct with two lanes of traffic in each direction.

[1] The project was completed shortly after the opening of the Brooklyn-Battery Tunnel in 1950, and provides direct access between the West Side Highway and FDR Drive.

[5] In 2005, during the reconstruction of NY 9A, the western end of the Battery Park Underpass was extended to the north by about 25 feet (7.6 m) to provide a U-turn lane and amenities for pedestrians and bicyclists.

[6] During Hurricane Sandy, the tunnel was filled with seawater and required major repairs.

[7] There have been three proposals to extend the tunnel north on the FDR Drive side.