New York City, officially the City of New York, historically New Amsterdam, the Mayor, Alderman, and Commonality of the City of New York, and New Orange, by-name the Big Apple, city and port located at the mouth of the Hudson River, southeastern New York state, northeastern U.S. It is the largest and most influential American metropolis, encompassing Manhattan and Staten islands, the western sections of Long Island, and a small portion of the New York state mainland to the north of Manhattan.