Which New York City borough is not served by the New York City Subway?

Staten Island is the New York City borough not served by the New York City Subway.

The Subway serves four of the city’s five boroughs: Manhattan, Brooklyn, Queens and the Bronx. Staten Island instead has its own rapid-transit line, the Staten Island Railway, which is operated by the Metropolitan Transportation Authority but is not physically connected to the New York City Subway network.

This distinction causes occasional confusion because the Staten Island Railway uses subway-like electric trains, stations and fares in parts of its history, yet it is treated as a separate system. Riders cannot travel directly from a Staten Island Railway platform onto a Subway train; connections require a bus, ferry or other transport.

The Staten Island Ferry provides the best-known link to Manhattan, while the island’s rail line runs mainly along its eastern side between St. George and Tottenville. The New York City Subway itself grew from three formerly separate systems—the IRT, BMT and IND—which were unified under city ownership in 1940. Staten Island’s separate railway was not incorporated into that network.