Staten Island is a borough and county in New York City, New York, United States. It is coextensive with Richmond County and serves as the southernmost of the five boroughs and counties within the city. Geographically, it is located at the southernmost point of the State of New York.
The borough is defined by its surrounding waterways. It is separated from the state of New Jersey by the tidal straits known as Arthur Kill and the Kill Van Kull. To the north, it is separated from the rest of New York by New York Bay.