New York City worldwide. New York City is situated in the Northeastern United States, in southeastern New York State, approximately halfway between Washington, D.C. and Boston. The location at the mouth of the Hudson River, which feeds into a naturally sheltered harbor and then into the Atlantic Ocean, has helped the city grow in significance as a trading port. Most of New York City is built on the three islands of Long Island, Manhattan, and Staten Island. The Hudson River flows through the Hudson Valley into New York Bay. Between New York City and Troy, New York, the river is an estuary. The
New York (state) arises as a cuesta east of Lake Ontario. "Upstate" and "downstate" are often used informally to distinguish New York City or its greater metropolitan area from the rest of New York State. The placement of a boundary between the two is a matter of great contention. Unofficial and loosely defined regions of Upstate New York include the Southern Tier, which often includes the counties along the border with Pennsylvania, and the North Country, which can mean anything from the strip along the Canada–US border to everything north of the Mohawk River. New York contains a part of the Marcellus shale,