The county was created by the Michigan Legislature in 1840 as Kanotin County, and renamed Iosco County in 1843. It was administered by a succession of other Michigan counties prior to the organization of county government in 1857. A majority of the population used to be Chippewa Indians, the area offered shelter from tall white pines, and food from the river and lake. Iosco County was cut from a piece of land seded from the Chippewa Indians to the United States Government. Then, in the 1800s when the lumber boom hit, many more people moved to the area.