 According to the United States Census Bureau, the township had a total area of 21.52 square miles (55.735 km2), including 21.334 square miles (55.254 km2) of land and 0.186 square miles (0.481 km2) of water (0.86%),

Municipalities bordering the township are Bordentown Township, Mansfield Township, North Hanover Township, Springfield Township in Burlington County; and Hamilton Township in Mercer County.Unincorporated communities, localities and place names located partially or completely within the township include Crosswicks, Davisville and Extonville.The census statistics above include residents of a state youth detention center located at the northwest edge of Chesterfield Township, on the border with Hamilton Township.