Montmorency County is a county located in the U.S. state of Michigan. As of the 2020 census, the population was 9,153, making it the second-least populous county in Michigan's Lower Peninsula, behind its southern neighbor, Oscoda County. The county seat is Atlanta.

Cheboygan County is a county in the U.S. state of Michigan. As of the 2020 census, the population was 25,579. The county seat is Cheboygan. The county boundaries were set off in 1840, with land partitioned from Michilimackinac County. The Cheboygan County government was organized and combined with the former Wyandot County in 1853.