Actually Scotsman is pretty close to right, as is Kel in his observation. It did originate mainly in Appalachia, however there were very few settlers there that weren't from Ireland, Scotland, Wales and to a lesser extent England. Where I'm from also was settled by Germans and Poles, and Czechs, so you find that country music from Texas in the earlier days contained more brass instruments and waltzes as well as the influence from those from the British Isles.
But country music as we know it, the music from Nashville derived mainly from the bluegrass styles of the Virginias, Kentucky, and Tennessee which were primarily Scot and Irish and Welsh. As time as gone by, and other regions of the country where settlers from other parts of the world hailed from moved into the country music business, you got more of an amalgamation of influence.
That was a long way to simply say that I agree with both Scotsman and Kel!