Greenfield Township is one of the sixteen townships of Warren County, Iowa, United States. Its estimated population as of 2008 is 5,773 people, with a density of 138 people per square mile (53 people/km2). Three cities have land in Greenfield (Norwalk, Spring Hill, and Des Moines—the state capital), as well as two unincorporated areas (Greenbush and Scotch Ridge). The township has two cemeteries (Webb Cemetery and North Ridge).