Carrickabraghy Castle is located on an outcropping of rock at the southern entrance of Trawbreaga Bay in the Inishowen Peninsula, County Donegal. The castle protected a small peninsula in north-western Inishowen known as the Isle of Doagh. (It was an island once in prehistory).
In pre-Viking years, Carrickabraghy (as well as the Isle of Doagh) was ruled by the Cenel Coelbad, descendants of Eoghan (who was son of the Irish High King, Niall of the Nine Hostages). Coelbad was the grandson of Eoghan. Many Irish septs are descended from the kings of Carrickabraghy, including my own (O’Gaillin). From forts located at the site of the present castle, the kings of Carrickabraghy defended Inishowen from attacks.
From the 9th century onward,the land was ruled by the O Maolfabhail (McFall) sept who protected Inishowen from Viking raids and raids by other foreigners.
Sometime after 1200 AD, the rulers of Inishowen came from the O Dochartaigh (O’Doherty) clan. Carrickabraghy Castle was probably built around 1590 by Phelim Brasleach O’Doherty. It was one of a chain of several O’Doherty castles that protected the peninsula. The castle was originally built with a keep and two towers surrounded by a bawn wall. Today the castle ruins has only the keep and part of one tower.
One of the castle’s famous residents was young Sir Cahir O’Dohery, Lord of Inishowen. Cahir took the English side in the Nine Years War with the Irish Earls. At the conclusion of the war, he was suspected of planning to retake Ireland with help from Spain. He began a poorly conceived rebellion in 1608 when he captured and burned Derry City, Strabane, and other English controlled sites before being defeated and killed near the Rock of Doon in Kilmacrenan, Donegal.
This video by Peter Homer is an aerial view of the castle.