IRT Flushing Line station In 1913, the New York City Public Service Commission formalized the
Dual Contracts, specifying new lines or expansions to be built by the
Interborough Rapid Transit Company (IRT) and the
Brooklyn Rapid Transit Company. As part of the Dual Contracts, the IRT was to complete and open the
Steinway Tunnel as part of the new
Flushing subway line. The tunnel, running under the
East River with trolley loops on both the Manhattan and Queens sides, had sat unused since 1907, when test runs had been performed in the then-nearly-complete tunnel. The route was to go from Times Square through the tunnel over to
Long Island City and from there continue toward
Flushing. The first part of the future IRT Flushing Line, from
Grand Central–42nd Street in Manhattan to
Vernon–Jackson Avenues in Long Island City, opened in 1915 and was extended to
Hunters Point Avenue in February 1916. The IRT's 45th Road–Court House Square station opened on November 5, 1916, as part of a two-stop extension of the line from Hunters Point Avenue to
Queensboro Plaza. The city government took over the IRT's operations on June 12, 1940. The IRT routes were given numbered designations in 1948 with the introduction of
"R-type" rolling stock, which contained
rollsigns with numbered designations for each service. The route from Times Square to Flushing became known as the
7. In 1949, the
New York City Board of Transportation announced that the Flushing Line platforms would be lengthened to 11 IRT car lengths; the platforms were only able to fit nine 51-foot-long IRT cars beforehand. The platforms at the station were extended in 1955–1956 to accommodate 11-car trains. However, nine-car trains continued to run on the 7 route until 1962, when they were extended to ten cars. In 2005, the station was listed on the
National Register of Historic Places. On August 19, 1933, the IND opened the Court Square station as part of the first leg of the IND Crosstown Line. The IND Queens Boulevard Line between Manhattan and
Roosevelt Avenue opened that same day, with trains (predecessor to today's G service) operating between
Queens Plaza and
Nassau Avenue in Brooklyn. The Queens Boulevard Line station, provisionally called "21st Street/Van Alst Avenue," was constructed between 1931 and 1933 along with the original section of the line east to Roosevelt Avenue. Although the station had been completed, This was in spite of protests from local civic and industry leaders, due to the numerous factories in the surrounding area. By December 1933, the station was referred to as "Ely Avenue", likely to avoid confusion with the
nearby station on the Crosstown Line. The station was finished by 1938, but its opening was delayed once again due to alleged lack of demand, with calls to open the station to serve the
Long Island City Courthouse, St. John's Hospital (now the site of
One Court Square), and the newly opened
Queensbridge Houses. The Queens Boulevard Line station finally opened as 23rd Street–Ely Avenue on August 28, 1939, six years after the first section of the Queens Boulevard Line and the opening of Court Square station on the Crosstown line. until many named streets in the borough were given numbers by the Queens Topographical Bureau in 1915. Similarly, Van Alst Avenue is now 21st Street, while the former Nott Avenue is the present-day 44th Drive. The building opened in 1989, with the passageway completed later on. On December 16, 2001, the 63rd Street Line connector was opened and service on the Queens Boulevard Line was increased, requiring G trains to terminate at Court Square on weekdays. To compensate Crosstown riders going into Queens, a free out-of-system transfer to the Flushing Line station was created. The moving walkway was subsequently found to have limited benefits: it saved commuters an average of 9 seconds; was often out of service; and could only operate in one direction toward the Queens Boulevard Line platforms. In October 2005, Citigroup announced they would be funding the passageway between the Flushing and Crosstown line stations, as a zoning requirement for the construction of the Court Square Two building. On March 17, 2011, the Queens Boulevard station was renamed to "Court Square–23rd Street". Most of the project was funded by Citigroup, but $13.9 million was covered by the MTA. The elevator project was originally expected to begin in 2018. However, after the
14th Street Tunnel shutdown was announced in 2016, the project was placed on hold in favor of capacity improvements to accommodate displaced riders on the
14th Street Tunnel, used by riders of the . Two staircases between the IND Crosstown Line platform and the mezzanine were widened and two new staircases added, and the moving walkways were removed, providing additional capacity. In December 2021, the MTA awarded a contract for the installation of elevators at eight stations, including the Crosstown Line platform at the Court Square station, replacing one of the stairways which had been added in 2018. The project was scheduled to be completed in March 2023, but completion was pushed back to mid-July of that year. In December 2019, the MTA announced that the Queens Boulevard Line platforms would become ADA-accessible as part of the agency's 2020–2024 Capital Program. With the construction of the
Skyline Tower above the station in the late 2010s, its developer spent $17 million to construct a new entrance to the Queens Boulevard Line's westbound platform, which opened in March 2021. A future developer will construct an elevator from the westbound Queens Boulevard Line platform to the mezzanine. The MTA began receiving bids for the construction of a ramp to the eastbound platform in May 2023, and the contract was awarded that December. In April 2025, the Court Square–23rd Street station became one of the first New York City Subway stations to have all their
MetroCard vending machines removed, amid the replacement of the MetroCard with the
OMNY fare payment system. ==Station layout==