AnnaS:

The term "Michiganders" was coined by Ohioans as a pejorative term, apparently around the time that Michigan and Ohio had a border war. My memory of high school history class is hazy, but I recall that the single battle was fought in a farm field, resulting in casualties of a couple of geese and some cabbage heads. The dispute was settled, with Ohio getting the strip of land, including Toledo, and Michigan getting the entire upper peninsula. Despite the term "Michiganders," it seems it was the Ohioans who got plucked.

Natives of Michigan are now variously called Michiganians and Michiganders. Neither term bothers.