Woodcliff Lake is the name of a reservoir in Woodcliff Lake and portions of Hillsdale and Park Ridge, in Bergen County, New Jersey, United States. It was created circa 1903 by damming the Pascack Brook and is also fed by the Bear Brook which joins the Pascack at the reservoir. The creation of the lake led what had been the Borough of Woodcliff to change its name to Woodcliff Lake, to match the name of the new reservoir.