Scots-IrishScots-Irish is a term used to refer to ancestors of the current inhabitants of Northern Ireland who emigrated to North America. Also known as Ulster Scots. Significant numbers of them settled on the American frontier, at the time of their immigration, the Appalachian Mountains. Large numbers of their descendants moved into the Ohio River and central Mississippi River valleys.
(The alternative Scotch-Irish is archaic, and now considered offensive. see Scotch.)