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
Millstone River of Philadelphia and New York. The Millstone River is an important tributary of the Raritan River. The Raritan River empties into the Raritan Bay, a bay of the Atlantic Ocean. The Raritan Bay is contiguous to New York Harbor and separates the New York City Borough of Staten Island (Richmond County) from Central New Jersey along with the Arthur Kill a more narrow channel of water between Staten Island and New Jersey. As the Raritan River flows eastward towards Raritan Bay, it joins the Millstone River flowing north in the vicinity of Bound Brook, New Jersey. The Millstone River traces