Oklahoma really doesn't fit in with Iowa or the Dakotas. It's just the South on Midwestern soil: mostly Baptist, very conservative, lots of guns and sweet tea and pickup trucks. It's flat, sure- but so is Arkansas.
You may be better off splitting the Midwest into a northern and a southern portion. This is most apparent in politics (the northern Midwest voted for Obama in the last two elections, which is unimaginable in Kansas or Oklahoma), but is more far-reaching than that.
Also, Cleveland, Detroit, Buffalo, and to an extent Pittsburgh (which however has undergone a resurgence in the last couple of decades) are all Rust Belt. That's definitely a cultural grouping: post-industrial cities and their hinterlands, mostly populated by Eastern Europeans and some Italians and Irish, with bad ghettos, that were much more prosperous and populated half a century ago.
everything besides scandoid masochism is RIGHTIST HITLEROFASCISM!!! IF WE DON'T DO A COMMUNISM NOW THEN THE BLUE DEVIL WILL EAT OUR RIGHTEOUS UTOPIA!!! GIVE US MONEY!!! and also россия cannot в europe hahahaha fuck u царистские ultraнацисты return to mongol idiot steppe uncivilized,,,,,hahaha fuck you russia ps give us our space shuttles back we cannot в space. we are advanced and superior give us our rightful space shuttle ride into space
i have just realised something looking at this map. Apart from the Southwest, where the liberal democrats are some sort of weird regional thing, almost all of the lib dem seats are on the borderline between tory and labour regions — there are no lib dem seats deep within the Labour tumours [except in glasgow]