Andover is a borough in Sussex County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 595, a decrease of 11 (−1.8%) from the 2010 census count of 606, which in turn reflected a decline of 52 (−7.9%) from the 658 counted in the 2000 census.

Newton, officially the Town of Newton, is an incorporated municipality and the county seat of Sussex County in the U.S. state of New Jersey, situated approximately 60 miles (97 km) northwest of New York City. As of the 2020 United States census, the town's population was 8,374, its highest decennial population ever, an increase of 377 (+4.7%) from the 2010 census count of 7,997, which in turn reflected a decrease of 247 (−3.0%) from the 8,244 counted in the 2000 census.