Macomb County is a county on the eastern shore of the U.S. state of Michigan. It is part of the Detroit metropolitan area, bordering Detroit to the north and containing many of its northern suburbs. Its seat of government is Mt. Clemens, and its largest community is Warren. As of the 2020 census, the county had a population of 881,217, making it the third-m…Macomb County is a county on the eastern shore of the U.S. state of Michigan. It is part of the Detroit metropolitan area, bordering Detroit to the north and containing many of its northern suburbs. Its seat of government is Mt. Clemens, and its largest community is Warren. As of the 2020 census, the county had a population of 881,217, making it the third-most populous county in the state, behind neighboring Wayne and Oakland.