Grand Rapids is a city in and county seat of Kent County, Michigan, United States. It had a population of 198,893 at the 2020 census, making it t…Grand Rapids is a city in and county seat of Kent County, Michigan, United States. It had a population of 198,893 at the 2020 census, making it the second-most populous city in Michigan, after Detroit. Grand Rapids is the central city of the Grand Rapids metropolitan area, which has a population of 1.16 million and a combined statistical area population of 1.5 million.