Allendale is an unincorporated community in Ottawa County in the state of Michigan. It is a part of the Grand Rapids-Muskegon-Holland, Michigan combined statistical area. It is an exurb of Grand Rapids, and its population at the 2010 census was 17,579.
The community is named after Agnes Allen, the first person on the tax roll in the area and the widow of Hannibal Allen, who was the son of Revolutionary War hero Ethan Allen.
The Grand Valley State University has its main campus in Allendale.
The population has a majority of White Americans. A small percentage of the population comprises people of African American and Hispanic origins.