Jenison is a census-designated place (CDP) in Ottawa County in the U.S. state of Michigan. The community is located within 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.

Ottawa County is a county located in the U.S. state of Michigan. As of the United States 2020 Census, the population was 296,200. The county seat is Grand Haven. The county is named for the Ottawa Nation, was set off in 1831 and organized in 1837. Ottawa County is included in the Grand Rapids-Kentwood, MI Metropolitan Statistical Area and has a significant Dutch American population.