Some have said it's because the Indians pronounced it that way in their language. I'm not so sure... I think the English (or French?) just spelled it wrong, and didn't want to admit to their mistake afterwards.
To make it even more interesting, there is a Mackinac Island with a town on it, and across the water on the mainland is a city called Mackinaw City. Mackinaw City is newer. One might think we Americans named the newer town 'Mackinaw' to right the previous wrong, but the story I got while visiting was the spelling was different to simplify mail delivery.
We had a fun visit to both places while Erika was here in October. Here's several photos of the Island and the city on the island.... (by the way, the only transportation on the island is by foot, bicycle or horse.... quite fun!).
