Mountain Whites were usually poor whites living in the Southern United States in Pre-Civil War America. They inhabited the valleys of the Appalachian range from western Virginia to northern Georgia and Alabama.
They were often isolated from the rest of Southern society and civilization. Because of this, they did not own slaves and were critical of the Southern economic system. As independent small farmers living on the harsh frontier, they were starkly different from the flatland whites. They were also able to retain many of their customs they brought over from Europe that had long since died out in Europe. There were reports of some isolated mountain whites speaking in Elizabethan accents, even as late as Civil War times.
Mountain whites also developed their own styles of music which borrowed from Scottish and Irish tradition as many were of Scots-Irish descent. The music of mountain whites contributed heavily to the formation of bluegrass music.They fought primarily for sectionalism and states' rights and also for Abolition. In the Civil War, the mountain whites were an important stronghold of Unionism within the Confederacy.
Source: Internet