The history of the O’Doherty clan, one of the illustrious Gaelic families of Co. Donegal, and the castles they built throughout the Inishowen peninsula, is recounted in this section. Carrickabraghy Castle, built in the 16th century, was occupied by the Doagh Branch of the Ó Docharthaigh. Gearalt , a member of that family, held the lordship of Inishowen from 1526-1540 and it was probably while he was chieftain that the castle was built. On Gearalt’s death the lordship returned to the Elagh Branch where it remained until the death of Cahir (Cathaoir), the last chieftain of Inishowen in 1608.