What shared traits do you see between Amarillo and Knoxville? Having visited both, Amarillo is distinctly High Plains/Western while Knoxville is Appalachian. Different cultures, geography, everything.

Yeah southern Indiana, Illinois, Ohio, northern Kentucky, and western Tennessee, the Ohio River Valley in essence, are culturally very similar and "appalachia-light".

But IMO that's a very far cry from eastern/south-eastern Kentucky, eastern Tennessee, western NC, WV, etc; truly core Appalachia.

Its also a far cry from mid-Indiana, which is culturally identical to northern Indiana, most of Illinois, Iowa, southern Michigan, maybe even as far as southern Wisconsin, Kansas, and Nebraska. That's Corn/Rust belt, very crop-farm oriented, dairy farms, extremely flat, but not as rural as many people think, not nearly as rural as Appalachia or the west.

It doesn't include SoCal. It stops in Monterey County/Big Sur.

Thinking about the map as monocultures is disingenuous. They have cultural focuses in common (among other things), which does not make them the same culture. Notably, these regions do not vote the same. It's not a party alignment map.

The ubiquity of Subarus, the BLM signs in front yards & the pride stickers don't convince you? Ever drive an hour or two away from the coast and notice the difference?

King George’s royal proclamation of 1763 established the “Indian Reserve” covering most of Ohio, Indiana, Illinois, Wisconsin, Michigan and Minnesota. European colonists were prohibited from trespassing - only a small number of British military outposts were allowed. Just a short time before the revolution, it got organized as part of Quebec.

Early in the revolution, it was taken by the colonists who declared it “Illinois County, Virginia” and allowed people to stream in and claim their homesteads (Note that the northern part was claimed by Connecticut as their own “Western Reserve”). Essentially all of southern Ohio, Indiana and Illinois was settled by people crossing the river from Kentucky, so it makes a lot of sense that you’d think that the southern parts of all these states seem more similar to each other than they are to their northern neighbors.

The next section north seems to have been mostly dominated by folks from the mid-Atlantic - Virginia, etc. And further north dominated by people that arrived on sailing ships, especially from New York. New Buffalo Michigan refers to Buffalo New York ;)

Anyway, it seems kind of weird that these states seem geographically oriented north-south but culturally oriented east-west. But the fact that they were depopulated (of Europeans) and then repopulated (by Europeans) gives an explanation of that, especially with the transportation available at the time of repopulation (of Europeans).

As someone who grew up in northern Indiana; 100%. Northern and middle-Indiana are pretty culturally identical, alongside southern Michigan, most of illinois, western Ohio, then extending further into e.g. southern Wisconsin and Iowa.

But southern Indiana is very different. Definitely more similar to Kentucky & Cincinatti-area southern Ohio. You start to get "twangs" of Southern Americana as you approach the Ohio River Valley, which are basically non-existent in northern Indiana. Something about the air is different.

The biggest cultural shock people not from the midwest, and even people from the midwest, often experience about the area is IME northern mainland/non-UP Michigan. Its a truly unique region that is dissimilar to almost anywhere else I've visited; like mixing the cultures of the New England coast with rural farms.