The Dwars Kill (also known as Dwarskill or Dwarskill Creek) is a tributary of the Hackensack River (Oradell Reservoir) in Bergen County, New Jersey, in the United States.The name is taken from the Dutch language and can be translated as Cross Creek, which may have been inspired by its generally westerly direction as it traverses today's towns of Alpine, Closter and Norwood to the south-flowing main river.