Geography of New York City the coast of the Northeastern United States at the mouth of the Hudson River in southeastern New York state. It is located in the New York–New Jersey Harbor Estuary, the centerpiece of which is the New York Harbor, whose deep waters and sheltered bays helped the city grow in significance as a trading city. Much of New York is built on the three islands of Manhattan, Staten Island, and western Long Island, making land scarce and encouraging a high population density. The Hudson River flows from the Hudson Valley into New York Bay, becoming a tidal estuary that separates the
New Jersey v. New York channel. This agreement was fashioned in order to allow New Jersey to build docks on the riverfront, while allowing New York to control islands that it already considered integral parts of its territory. This led to places such as Ellis Island located on the New Jersey side of the river, but belonging to New York. Between the 1890s and 1934, Ellis Island was expanded through land reclamation and soon became a major center for immigrants coming from Europe to the New World. This land was added by the federal government and considered part of New York for decades before New