34th Street–Penn Station is an express station on the IRT Broadway–Seventh Avenue Line of the New York City Subway. Located at the intersection of 34th Street and Seventh Avenue, it is served by the 1 and 2 trains at all times, and the 3 train at all times except late nights. Connections are available to the LIRR, NJ Transit and Amtrak at Pennsylvania Station.

The IRT Broadway–Seventh Avenue Line is a New York City Subway line. It is one of several lines that serves the A Division, stretching from South Ferry in Lower Manhattan north to Van Cortlandt Park–242nd Street in Riverdale, Bronx. The Brooklyn Branch, known as the Wall and William Streets Branch during construction, from the main line at Chambers Street southeast through the Clark Street Tunnel to Borough Hall in Downtown Brooklyn, is also part of the Broadway–Seventh Avenue Line. The IRT Broadway–Seventh Avenue Line is the only line to have elevated stations in Manhattan, with two short stretches of elevated track at 125th Street and between Dyckman and 225th Streets.