Donough O'Brien, 2nd Earl of Thomond (Irish: Donnchadh Ó Briain; died 1 April 1553), also known as "the fat",[1] was the son of Connor O'Brien, King of Thomond and Annabell Burke.
He inherited the earldom from his uncle, Murrough O'Brien, by special remainder.
He died on 1 April 1553, after being attacked by his brothers at the family seat of Clonroad.
O'Brien's brother Sir Donald was named king of Thomond by the Dalgais, but O'Brien's son, Connor, allied himself with the English and regained control of his lands.
[3] Children of Donough O'Brien and Helen Butler: