Jenison is an unincorporated community in Ottawa County in the U.S. state of Michigan. It is a census-designated place (CDP) for statistical purposes, but has no legal status as an incorporated municipality. The community is governed by Georgetown Charter Township. The population of the CDP was 17,211 as of the 2000 census. The current estimated population for the entire Jenison ZIP code, 49428, is 25,770. The geographical boundaries of the ZIP code are larger than that of the CDP.