Tirkeeran (from the Irish Tír Mhic Caoirthinn, meaning "land of Cartin") is a barony of County Londonderry. In the north it is on the Londonderry coastline and it extends inland. Tirkeen is bordered by four other baronies: Keenaght to the east; Strabane Lower to the south-east; North West Liberties of Londonderry to the west; Strabane Upper to the south.
Tirkeeran derives its name from the territory of the Airgiallan clan the Ui Mhic Carthainn (MacCarthain), one of the earliest tribes in the area based to the southeast of Lough Foyle. The MacCarthain claim descent from Forgo mac Carthainn, the great-great-grandson of Colla Uais.
Dunchad mac Ultain is cited as king of the Ui Meic Cairthinn in 677, when he was killed by the king of the Cenél nEóghain, Mael Fithrich. It was around this period that the Cenél nEóghain were attempting to expand eastwards from their homeland in Innishowen, in modern day County Donegal and into central Ulster. Eventually the Cenél nEóghain crushed the power and independence of the MacCarthain and subjugated them, however it would remain in some minor form until the end of the eleventh century when the Annals cite Conchobhor ua hAinniaraidh, king of Cianachta and Ua Cein king of the Ui Meic Carithinn fell by each other in combat.
By the 12th century, the area of Tirkeeran was divided into three districts, given as belonging to the Ó Eiteagain (O'Ettigans) in the 12th century: Teallach Caghalain; Teallach Duibhailbe; and Teallach Braeain. Prior to the 13th century the septs of Ó Cairealláin (O'Carolan) and Mac Eiteagain (MacEttigan) are cited as ruling the territory of Clann Diarmatta (south-east of Lough Foyle), which contained the present-day parish of Clondermot (which derives its name from the territory). These septs descend from the Cenél nEóghain branch Clann Conchúir Magh Ithe (Clan Connor of Moy Ith), of which the O'Cahans were the principal sept and who would later dominate and rule a territory spanning the baronies of Tirkeeran, Keenaght, and Coleraine.
When the baronies of Ulster were being created around 1585, the general manner was to name it after the principal town or castle lying within the area, in which they held their court, baron, and gaol. An attempt was made to rename the lands of Tirkeeran the "Barony of Annagh", after the lord of the districts castle, which stood on an island in Lough Enagh, but the ancient, established territorial name was maintained instead.
The civil parishes of Tirkeeran are:
- - Logainm - Barony of Tirkeeran
- PRONI Baronies of Northern Ireland
- Bready History; Chapter 1
- Cartin, Edward; Cartin; One of the oldest surnames in Ulster?
- Cartin, Edward; Where did and do the Ui Mhic Carthainn live?
- The book of Irish families, great and small
- Ireland's History in Maps - The baronies of Ireland
- Ireland's History in Maps - The Northern Uí Neill
- Map of the baronies and civil parishes of County Londonderry