I worked with a guy who had a strong Southern accent, I asked him where he's from. Turns out he was born and raised in Bonanza, a little town by me. What's with the accent?.. said he was in the army, after a couple of months, everybody had a Southern accent.
Right. There is a whole lot of variance in regional accents even within the same basic geographical sub-regions.
That's for sure for a lot of the population but there are still big differences. One time a woman from Alabama told me she liked my "yeller" shirt. She wasn't a redneck but I don't think she had been exposed to much of the world.