Located at 45th Street and Fourth Avenue in Sunset Park, Brooklyn, it is served by the R train at all times.

[6] The 45th Street station was constructed as part of the Fourth Avenue Line, the plan for which was initially adopted on June 1, 1905.

[14][15] Though the Transit Commission ordered the BMT to lengthen these platforms in September 1923, no further progress was made until February 16, 1925, when the New York City Board of Transportation (NYCBOT) commissioned its engineers to examine platform-lengthening plans for this and eleven other stations along the Fourth Avenue Line.

[19][20] In the 1960s, the New York City Transit Authority (NYCTA) started a project to lengthen station platforms on its lines in Southern Brooklyn to 615 feet (187 m) to accommodate 10-car trains.

[6] On July 14, 1967, the NYCTA awarded a contract to conduct test borings at eleven stations on the Fourth Avenue Line, including 45th Street, to the W. M. Walsh Corporation for $6,585 (equivalent to $60,172 in 2023) in preparation of the construction of platform extensions.

The latter change, which was also made to 15 other stations on the BMT Broadway and Fourth Avenue Line, was criticized for being dehumanizing.

The NYCTA spokesman stated that the old tiles were in poor condition and that the change was made to improve the appearance of stations and provide uniformity.

[29] Columns run along the entire length of both platforms at regular intervals and are painted dark grey-blue.

The gray cinderblock field contains the station-name signs and white text pointing to the exits.

Evidence of this includes a gated door on the platform wall and adjacent "EXIT" signs.

[38][39] The northwest corner exit was closed after it was accidentally destroyed by nearby construction workers.

The New York City Transit Authority promised to comply with the wish of the board, and the entrance was closed.