Calvagh O'Donnell, eldest son of Manus O'Donnell, was an Irish King of Tyrconnell of the mid-16th century. He was king and chief of the O'Donnell dynasty based in Tyrconnell in western Ulster. He is best known for his conflict with Shane O'Neill – a dispute that involved the intervention of the English government in Ireland on Calvagh's side.
- Occupation
- ruler
- Citizenship
- Kingdom of Ireland
- Born
- 1515
- Died
- October 26, 1566
