thumb|upright=1.2|Hopewell Township is marked yellow on the 1862 map of Cumberland County
Hopewell Township is a township in Cumberland County, in the U.S. state of New Jersey. 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. As of the 2020 United States census, the township's population was 4,391,
Hopewell Township was first formed as a precinct on January 19, 1748, and was incorporated by an act of the New Jersey Legislature on February 21, 1798, as one of New Jersey's initial group of 104 townships. Portions of the township have been taken to form Columbia Township (March 12, 1844, returned to Hopewell Township on March 11, 1845), Cohansey Township (March 6, 1848) and Shiloh borough (April 9, 1929).
Geography
According to the United States Census Bureau, the township had a total area of 30.87 square miles (79.96 km<sup>2</sup>), including 29.89 square miles (77.42 km<sup>2</sup>) of land and 0.98 square miles (2.54 km<sup>2</sup>) of water (3.18%).
The township borders the municipalities of Bridgeton, Fairfield Township, Greenwich Township, Shiloh, Stow Creek Township and Upper Deerfield Township in Cumberland County; and Alloway Township in Salem County.
Mary Elmer Lake is a reservoir on the Cohansey River in Hopewell Township and Bridgeton that covers and is used for water-supply and recreation purposes. Sunset Lake is a reservoir in Hopewell Township and Upper Deerfield Township covering that was created by damming a stream that feeds to the area from above Seeley Lake and a stream that feeds into the lake from nearby Mary Elmer Lake.