Greenwich Township is the westernmost township in Cumberland County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 771, a decrease of 33 (−4.1%) from the 2010 census count of 804, which in turn reflected a decline of 43 (−5.1%) from the 847 counted in the 2000 census. It is part of the Vineland-Bridgeton metropolitan statistical area, which encompasses those cities and all of Cumberland County for statistical purposes and which constitutes a part of the Delaware Valley.

Cumberland County is a coastal county located on the Delaware Bay in the Southern Shore Region of the U.S. state of New Jersey. As of the 2020 census, the county was the state's 16th-most-populous county, with a population of 154,152, a decrease of 2,746 (−1.8%) from the 2010 census count of 156,898. Its county seat is Bridgeton. Cumberland County is named for Prince William, Duke of Cumberland. The county was formally created from portions of Salem County on January 19, 1748. The county is part of the South Jersey region of the state.