Deerfield Township is a township in Cumberland County, New Jersey, United States. It is part of the Vineland-Millville-Bridgeton Primary Metropolitan Statistical Area for statistical purposes. As of the 2010 United States Census, the township's population was 3,119, reflecting an increase of 192 (+6.6%) from the 2,927 counted in the 2000 Census, which had in turn declined by 6 (-0.2%) from the 2,933 counted in the 1990 Census.
Deerfield Township was 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 were taken to form Bridgeton Township (March 3, 1845) and Upper Deerfield Township (February 23, 1922).