Indiana is a special case. Evansville is the South. Fort Wayne is still Rust Belt, Valparaiso is definitely Midwest. That’s actually an interesting way to approach it — to define where my boundaries of the Midwest run. I think it begins around Columbus, Ohio — Thurberville — and stretches west. Anything below I-70 is basically southern. And that’s true right across Missouri. My Midwest is bounded on the south by I-70. It stretches all the way to about an hour east of Denver and includes pretty much all of the Great Plains states north of I-70… You can take all of Kansas, some of Oklahoma, too. But not, for example, downstate Illinois. You start hearing the South in people’s voices. They don’t sound like Tom Brokaw anymore.
Inasmuch as I-70 runs through the northern half of Kansas, you can’t take any of Oklahoma, not even Midwest City, Oklahoma.
From the purely-historical standpoint, it makes more sense to me to put the boundary, not along I-70, but along US 40, the old National Road. Still, it’s hard for me to think of Terre Haute — even the south side of Terre Haute — as “basically southern.”