Real response to get some shit started:
Core Midwest: Ohio, Indiana, Illinois, Iowa
Upper Midwest: Michigan, Minnesota, Wisconsin
Outer Midwest: ND, SD, Nebraska (parts at least)
I will never recognize: Missouri
Everything else below Nebraska is "Plains" IMO.
South of the Ohio River is upper south.
Western PA and Pittsburgh can be "Midwest" if it wants, but the rest of PA isn't and the majority of the state doesn't qualify, so we'd have to balkanize.