High Quality Content by WIKIPEDIA articles! Earl of Antrim is a title that has been created twice, both times in the Peerage of Ireland and both times for members of the MacDonnell family, originally of Scottish origins. This family descends from Sorley Boy MacDonnell, who established the family in County Antrim. His fourth son Randal MacDonnell was created Viscount Dunluce, in the County of Antrim, in 1618, and Earl of Antrim in 1620. Both titles were in the Peerage of Ireland. His eldest son, the second Earl, fought as a Royalist in the Civil War and was created Marquess of Antrim in the Peerage of Ireland in 1645. He was childless and on his death in 1682 the marquessate became extinct.