The Scotch-Irish began emigrating to Northern Ireland from Scotland in the seventeenth century to form the Ulster Plantation. In the next century these Scottish Presbyterians migrated to the Western Hemisphere in search of a better life. Except for the English, the Scotch-Irish were the largest ethnic group to come to the New World during the eighteenth century. By the time of the American Revolution there were an estimated 250,000 Scotch-Irish in the colonies, about a tenth of the population. Twelve U.S. presidents can trace their lineage to the Scotch-Irish. This work discusses the life of the Scotch-Irish in Ireland, their treatment by their English overlords, the reasons for emigration to America, the settlement patterns in the New World, the movement westward across America, life on the colonial frontier, Scotch-Irish contributions to America's development, and sites of Scotch-Irish interest in the north of Ireland.