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.