Saint Ignace, usually written as St. Ignace, is a city in the U.S. state of Michigan. As of the 2000 census, the city population was 2,678. It is the county seat of Mackinac County. From the Lower Peninsula, St. Ignace is the gateway to the Upper Peninsula. St. Ignace Township is located just to the north of the city, but is politically independent. Located in Michigan's Upper Peninsula, St. Ignace is at northern end of the Mackinac Bridge and Mackinaw City is to its south.