River Edge 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 12,049, an increase of 709 (+6.3%) from the 2010 census count of 11,340, which in turn reflected an increase of 394 (+3.6%) from the 10,946 counted in the 2000 census.

The Hackensack River is a river, approximately 45 miles (72 km) long, in the U.S. states of New York and New Jersey, emptying into Newark Bay, a back chamber of New York Harbor. The watershed of the river includes part of the suburban area outside New York City just west of the lower Hudson River, which it roughly parallels, separated from it by the New Jersey Palisades. It also flows through and drains the New Jersey Meadowlands. The lower river, which is navigable as far as the city of Hackensack, is heavily industrialized and forms a commercial extension of Newark Bay.