Northern Illinois and southern Wisconsin are the same state culturally and historically northern Illinois was fully part of the dairy belt.
A little history that makes a big dfference in who you will be rooting for:
“Were it not for the action of an enterprising lawyer 200 years ago, the northern portion of Illinois would have the badger as the state animal and the Green Bay Packers as the home football team... the move by Nathaniel Pope, the Illinois territory’s delegate in Congress, to relocate the original proposed boundary from the southern tip of Lake Michigan is regarded as a decisive event in Illinois history.”
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Boundary maneuver kept Northern Illinois from becoming part of Wisconsin
The Green Bay Packers could have been Chicago’s home team ...
thesouthern.com
So there it is. Everything from the level of the south tip of Lake Michigan northerly would have been in the Dairy State. And all you Bear fans living North of Calumet City and Orland Park all the way west to north of East Moline would be Badger and Pack fans. Downtown Chicago dressed up in Wisky colors. Yikes!