The Paulins Kill (also known as Paulinskill or Paulinskill River) is a 28.6 mile (46 km) long tributary of the Delaware River in northwestern New Jersey in the United States. It is New Jersey's third largest contributor (behind the Musconetcong River and Maurice River) to the Delaware River in terms of long-term median flow?flowing at a rate of 76 cubic feet of water per second (2.15 m³/s).[5] The Paulins Kill drains an area of 176.85 square miles (458 km²) across portions of two counties (Sussex and Warren) consisting of eleven municipalities. The Paulins Kill, which flows southwest from its source near Newton, New Jersey, is located at the border of the Appalachians and New York-New Jersey Highlands physiographic provinces.