 The county seat is St. Ignace.Formerly known as Michilimackinac County, in 1818 it was one of the first counties of the Michigan Territory, as it had long been a center of French and British colonial fur trading, a Catholic church and Protestant mission, and associated settlement.The county's name is believed to be shortened from ""Michilimackinac"", which referred to the Straits of Mackinac area as well as the French settlement at the tip of the lower peninsula.