Oradell 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 8,244, an increase of 266 (+3.3%) from the 2010 census count of 7,978, which in turn reflected a decline of 69 (-0.9%) from the 8,047 counted in the 2000 census. The borough includes a dam on the Hackensack River that forms the Oradell Reservoir. Oradell is a suburb of New York City, located approximately 15 miles (24 km) northwest of Midtown Manhattan.

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.