New York City Hudson River separates the city from the U.S. state of New Jersey. The East River—a tidal strait—flows from Long Island Sound and separates the Bronx and Manhattan from Long Island. The Harlem River, another tidal strait between the East and Hudson Rivers, separates most of Manhattan from the Bronx. The Bronx River, which flows through the Bronx and Westchester County, is the only entirely fresh water river in the city. The city's land has been altered substantially by human intervention, with considerable land reclamation along the waterfronts since Dutch colonial times; reclamation is most prominent in Lower Manhattan, with developments
River Vale, New Jersey section bordering Emerson to the south, Harrington Park to the southeast, Old Tappan to the east, and Pearl River, New York to the north. Its borders are defined by the Hackensack River to the east, which was dammed to form Lake Tappan, and Pascack Brook to the south. The northern border is defined by the New York-New Jersey state border. The western border has several sections, including a section defined by an unnamed creek and a section defined by Cedar Lane. The southern portion of the township lies between the Hackensack River and Pascack Brook, and is relatively flat. The