Re: Maybe someone from Wisconsin can answer this
It goes back to the Toledo War. In a nutshell...the strip of land that borders Michigan in Northern Ohio was given to Ohio and in return Michigan got the UP (Upper Peninsula). The federal government thought that it was a "sterile region on the shores of Lake Superior destined by soil and climate to remain forever a wilderness." Soon after mineral deposits were discovered and the total amount of revenue from the UP of Michigan from those mines surpassed what California kicked out during the gold rush.
The part of the UP that sits directly above Wisconsin identifies closer with Wisconsin than it does Michigan. Tons of Packer fans up there. Once you get farther east the sports allegiances start to become more muddled. Tom Izzo and Steve Mariucci are both from the UP.
If you are intrigued by UP culture track down a copy of the movie "Escanaba In Da Moonlight." It's a movie about deer camp and might not translate that well outside of the upper midwest but for those who are from Northern Wisconsin, Minnesota, the UP, etc. it is one of the funniest movies ever made.