Scotch-Irish (or Scots-Irish) Americans are American descendants of Ulster Scots people (predominantly Ulster Protestants) who emigrated from Ulster (Ireland's northernmost province) to the United States during the 18th and 19th centuries. Their ancestors had originally migrated to Ulster mainly from the Scottish Lowlands and Northern England in the 17th century.
The term Scotch-Irish is used primarily in the United States, with people in Great Britain or Ireland who are of a similar ancestry identifying as Ulster Scots people. When King Charles I attempted to force these Presbyterians into the Church of England in the 1630s, many chose to re-emigrate to North America where religious liberty was greater. Later attempts to force the Church of England's control over dissident Protestants in Ireland led to further waves of emigration to the transatlantic colonies
Wiki on Scottish Irish
