Woodcliff Lake is a borough in Bergen County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 6,128, an increase of 398 from the 2010 census count of 5,730, which in turn reflected a decline of 15 from the 5,745 counted in the 2000 census. Most of the borough mandates a minimum lot size of 22,500 …Woodcliff Lake is a borough in Bergen County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 6,128, an increase of 398 from the 2010 census count of 5,730, which in turn reflected a decline of 15 from the 5,745 counted in the 2000 census. Most of the borough mandates a minimum lot size of 22,500 square feet for single-family homes, with portions on the borough's east zoned for 15,000 square feet and portions of the borough's northwest and southwest zoned for 30,000 square feet lots.