My, such an academic thread. I love it!!
It’s my observation that state boundaries have almost nothing to do with culture development. First of all boundaries are political, not "cultural". Second, many regions and areas were histporically settled before "states" were declared (most of the East Coast, some of the Southwest that were originally Mexico, etc. Southern "Illinois "as listed above is another good example)
In fact I often find the most intriguing cultural areas to be border areas that are generally slower to develop that central political areas.
For example, sports teams/fans are regional, not "state" oriented. For an obvious example, look at "NY" teams that are actually in New Jersey. But most fans root for the team closest to their home, nt necessarily their state.
Food examples are even more the case and we have discussed them here and there on RF. Sociologists, anthropologists, cultural historians, etc. call this "foodways" and there is a lot in the academic literature about it. But the down-home RF style works for me.[:)]