The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the state-run Metropolitan Transportation Authority (MTA).
Opened in 1904, the New York City Subway is one of the world's oldest public transit systems, one of the world's most used metro systems, and the metro system with the most stations. It offers service 24 hours per day on every day of the year, though some routes may operate only part-time.
The New York City Subway is the largest rapid transit system in the world by number of stations, with 472 stations in operation (424 if stations connected by transfers are counted as single stations). Stations are located throughout the boroughs of Manhattan, Brooklyn, Queens, and the Bronx. The Staten Island Railway is not officially considered part of the subway, as it lacks a rail link with the subway system, so passengers traveling between Staten Island and another borough must take the Staten Island Ferry or an MTA bus; free transfers are allowed to the subway and bus systems. The PATH in Manhattan and New Jersey and the AirTrain JFK in Queens both accept the subway's MetroCard but are not operated by the MTA and do not allow free transfers. However, the Roosevelt Island Tramway does allow free transfers to the MTA and bus systems, even though it is also not operated by the MTA.
The system is also one of the world's longest. Overall, the system contains 236 miles (380 km) of routes, translating into 665 miles (1,070 km) of revenue track; and a total of 850 miles (1,370 km) including non-revenue trackage.
By annual ridership, the New York City Subway is the busiest rapid transit rail system in both the Western Hemisphere and the Western world, as well as the eighth busiest rapid transit rail system in the world; only the metro (subway) systems in Beijing, Shanghai, Seoul, Guangzhou, Tokyo, Moscow, and Hong Kong record higher annual ridership. In 2017, the subway delivered over 1.72 billion rides, averaging approximately 5.6 million daily rides on weekdays and a combined 5.7 million rides each weekend (3.2 million on Saturdays; 2.5 million on Sundays). On September 23, 2014, more than 6.1 million people rode the subway system, establishing the highest single-day ridership since ridership was regularly monitored in 1985.
Of the system's 27 services, 24 pass through Manhattan, the exceptions being the G train, the Franklin Avenue Shuttle, and the Rockaway Park Shuttle. Large portions of the subway outside Manhattan are elevated, on embankments, or in open cuts, and a few stretches of track run at ground level. In total, 40% of track is above ground. Many lines and stations have both express and local services. These lines have three or four tracks. Normally, the outer two are used for local trains, while the inner one or two are used for express trains. Stations served by express trains are typically major transfer points or destinations.
As of 2018, the New York City Subway's budgetary burden for expenditures was $8.7 billion, supported by collection of fares, bridge tolls, earmarked regional taxes and fees, as well as direct funding from state and local governments. Its on-time performance rate was 65% during weekdays.