Hopewell is a borough in Mercer County, in the U.S. state of New Jersey. Centrally located within the Raritan Valley region, this historical settlement is an exurban commuter suburb of New York City in the New York metropolitan area as defined by the United States Census Bureau. As of the 2020 United States census, the borough's population was 1,918, a decrease of 4 (−0.2%) from the 2010 census count of 1,922, which in turn had reflected a decline of 113 (−5.6%) from the 2,035 counted in the 2000 census.

Hopewell Township is a township in Mercer County, in the U.S. state of New Jersey. Located at the cross-roads between the Delaware Valley region to the southwest and the Raritan Valley region to the northeast, the township considered an exurb of New York City in the New York metropolitan area as defined by the United States Census Bureau, while also directly bordering the Philadelphia metropolitan area, being a part of the Federal Communications Commission's Philadelphia Designated Market Area. As of the 2020 United States census, the township's population was 17,491, its highest decennial count ever and an increase of 187 (+1.1%) from the 2010 census count of 17,304, which in turn reflected an increase of 1,199 (+7.4%) from the 16,105 counted in the 2000 census.