Sussex 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 2,024, a decrease of 106 (−5.0%) from the 2010 census count of 2,130, which in turn reflected a decline of 15 (−0.7%) from the 2,145 counted in the 2000 census.

Wantage Township is a township in Sussex County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 10,811, a decrease of 547 (−4.8%) from the 2010 census count of 11,358, which in turn reflected an increase of 971 (+9.3%) from the 10,387 counted in the 2000 census.