Is Virginia in the South? What parts?

[RINO Tom]

It's all part of the South, period.  What parts are "culturally Southern" (however you define that) is more subjective.

[RINO Tom]

I would keep the Southeastern VA megapolis in the South and extend it up most of the Delmarva Peninsula.  I went to the beach in Maryland this past summer, and any store you would walk into sold Confederate flag and pro-gun t-shirts.  Suffolk County, DE is roughly the northernmost extent of anything that can be described as the South along the Coast.

Here is the map I created a while back:

Your map is a cool idea (I couldn't make a better one), but it needs some work.  You went up way too high in Missouri, IMO (rural + cultural conservative =/= Southern ... being culturally Southern actually means something, usually drawing upon sympathies during the Civil War and migration patterns, not how religious or "rednecky" a place is) and definitely too high in Illinois.  You are counting counties that are part of the Metro East (Illinois suburbs of St. Louis) as "culturally Southern," and that's way off.  The area is incredibly German, St. Louis is absolutely not a Southern city, however oddly it may fit into the Midwest at times and the counties in the Metro East voted Republican while their counterparts to the South did not during 1860, for one example.

[RINO Tom]

I think the best solution is to think of the South as three areas - Appalachian South, Deep (or Gulf) South and Atlantic South. Then VA is easily in the Atlantic South since that matches the largest part of its population. NC and maybe SC is in that region, too. GA, AL, MS, and LA are the deep South. AR, TN, KY, and WV would fall in the Appalachian South by that measure. Of course its easier to make the split at the county level, but that's the issue with many states - their counties span more than one region.

Does Arkansas even lie in Appalachia?

Geographically no, but its demographics are pretty much exactly the same as a place like TN.  There are some areas that I would consider more "Deep South," particularly around the Mississippi, but most of the state is inhabited by (and descendants of) the same Scots-Irish group that moved west from VA and the Carolinas when those areas opened up for settlement, and that you find in places like TN and KY.

I just don't understand this type of thinking.  I think talking about the "cultural South" and where its boundaries lie is interesting, but these are geographic regions.  Utah and Vermont looked like very, very similar states in the mid-20th Century on several levels, but they obviously were totally different regions.  You're talking about subregions, which is needless to say different, but I don't see the need to put AR in an Appalachian region when it has none of the mountains.  Appalachia extends into PA, a Northeastern state; the subregion doesn't have to be homogeneous.  I don't know, I just think this type of thinking leads (other) people to say dumb things like "Wississippi" (because it's so unbelievable WI could just vote for a Republican without sharing any cultural connection to any part of the South).

[RINO Tom]

Wouldn't say I got triggered, LOL.  Just used "Wississippi" as an example of how drawing cultural comparisons between two states to argue they are in the same region is silly, even if they border each other.  Other factors matter more like where they actually are.  Regions can and should vary substantially from state to state.