Are Maryland/Delaware/DC/Virginia Southern states?

[Bleach Blonde Bad Built Butch Bodies for Biden]

Maryland, Delaware, and DC may not be culturally Southern (for the most part), but geographically I classify every state beneath the Mason-Dixon line to Oklahoma and Texas as Southern - just as the Census does.

And Virginia literally housed the capital of the Confederacy.  I don't buy the argument that because it's a blue state now it's "no longer Southern".