Scotch-Irish is a term that originally used to refer to the first Scots who emigrated to North America in large numbers, coming from a community of Scots living in Northern Ireland, also known as Ulster Scots. The term has gradually become more widely used and usually includes a large number of people whose ancestors migrated as a result of the Highland Clearances and Lowland Clearances. The Scotch-Irish played a very important role in the settling of the American frontier, at the time of their original immigration, the Appalachian Mountains. Large numbers of their descendants moved into the Ohio River, Appalachian Mountains and central Mississippi River valleys. Daniel Boone, Davy Crockett and Andrew Jackson are famous examples of the Scotch-Irish.