A regional rather than co-incidence or State-level effect, surely?
Although the land area in the USA is far larger than in England where I live, there may be an analogue here, with the generic but distinctive Northern English tones.
How many English Southerners (like me) would be able to differentiate between Nottinghamshire, Yorkshire and Lancashire voices? Though with Midlands parentage I might identify the Nottingham from the other two.
They might be able to identify a North-East regional accent though, at least to thinking a visiting Middlesborough native might be a Geordie. (A "Geordie" is from Newcastle on Tyne, or that area, and though the two cities are about 30 miles apart their accents are too similar for outsiders to tell them apart.)
Similarly the other way of course.
It's probably common in most countries that have regional accents, that the voice does not follow administrative boundaries at all.
Once, on holiday in the foothills of the Pyrenees, I noticed the local accent seemed oddly closer to SW Midlands English than central French. More than that, the area also still has its own language as well as Standard French, though I don't how widespread it is.
