US Regions - Tennessee

[muon2]

Based on your coloration, I think I'd keep it with the Deep South. The four major metro areas Memphis, Nashville, Chattanooga and Knoxville basically split two and two between the Deep South and Appalachian regions, and Nashville is really in a separate category not entirely like Appalachia but in some ways more like the Ohio River valley (Evansville, Louisville, and even Cincinnati). Only eastern TN really matches the KY and WV profile you show for the Border South.

Personally I think the notion of a border south is somewhat misused. There is a region on both sides of the Ohio River that acts as a bridge between the Great Lakes and Deep South, but it's a mistake to use it only for the area south of the river. Just like the states north of the river have southern areas quite different than their population centers on the Great Lakes, so too do the states south of the river have a different style from west to east. The division by the river at the state level too much reflects Confederate sentiments than modern politics and demographics.

[muon2]

Just to clarify, the red region in the map looks pretty senseless if you look at the pink State all together. In this case, the final red region can potentially comprise the pink States in the Southwest or those in the North, but obviously not both.

What about "neither," the option that I support?

Neither is obviously an option for these maps, generally speaking. But as I try to make regions with at leats 4 States each, I'd still try to add one or two more States to the dark red core.

Of course it could be that the Outer South/Appalachia is just not a region with four states. That certainly can be the case given the other regions that you have established.