Scotch Irish, aka Scots-Irish, aka Ulster Scots

The people we call Scotch Irish, known in the old country as Ulster Scots, were largely descendants of mixed Germanic peoples who over many centuries had moved into and taken over the Scottish Lowlands. Beginning in the early seventeenth century many migrated to Ulster in Northern Ireland, and starting about 1715 the Scotch Irish began a massive migration to America. By 1775, when the War of the Revolution began, some quarter million had arrived. Most of them ended in the Back Country from Pennsylvania south into Georgia.

(Source: Jackson's Way: Andrew Jackson and the People of the Western Waters, by John Buchanan; John Wiley & Sons, 2001)