The 23rd Street station is a local station on the IRT Lexington Avenue Line of the New York City Subway. Located at the intersection of Park Avenue South and 23rd Street in Gramercy Park and Flatiron District, Manhattan, it is served by 6 trains at all times, <6> trains during weekdays in the peak direction, and 4 trains during late night hours.

The IRT Lexington Avenue Line is one of the lines of the A Division of the New York City Subway, stretching from Lower Manhattan north to 125th Street in East Harlem. The line is served by the 4, ​5, ​6, and <6> trains.