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 (+6.9%) from the 2010 census count of 5,730, which in turn reflected a decline of 15 (−0.3%) from the 5,745 counted in the 2000 census. Most of the borough mandates a minimum lot size of 22,500 square feet (2,090 m2) for single-family homes, with portions on the borough's east zoned for 15,000 square feet (1,400 m2) and portions of the borough's northwest and southwest zoned for 30,000 square feet (2,800 m2) lots.

Bergen County is the most populous county in the U.S. state of New Jersey. As of the 2020 United States census, the county's population was 955,732, its highest decennial count ever and an increase of 50,616 (+5.6%) from the 905,116 recorded at the 2010 census, which in turn reflected an increase of 20,998 (2.4%) from the 884,118 counted in the 2000 census. Located in the northeastern corner of New Jersey and its Gateway Region, Bergen County and its many inner suburbs constitute a highly developed part of the New York City metropolitan area, bordering the Hudson River; the George Washington Bridge, which crosses the Hudson, connects Bergen County with Manhattan. The county is part of the North Jersey region of the state.