The O'Regan Family Genealogical Web Site

The O'Regan Surname

"O" means grandson of, a leading descendant, or head of a family (clan). The Milesian chiefs were distinguished by "O" and "Mac". The prefixes are confined to purely native families. Usage was submerged under English governance and influence. The resurgence began in the late 19th century, many years after Catholic emancipation (1829 statute) and about the time of repeal of laws in the 1870s that had forbidden land ownership by Papists.

The O'Regan surname originated independently in more than one place. The most important and apparently powerful O Riagain family began in Counties Meath and Dublin. They were one of the Four Tribes of Tara (O Regan, O Hart, O Kelly and O Connell). This O'Regan Tribe was of Heremonian stock, descended from Rossa Failgeach, a son of Cathire More, King of Ireland in A.D. 144. His posterity included O Dunn, O Regan, Mac Colgan, O Hart and Mac Murraugh, all kings of Leinster (Book of Leacan and Book of of Ballymote). Along the line of descent was a chief, Riagain, who gave his name to Hy Riagain, now known as the barony of Tinnahinch, in County Leix. O Riagain means "descendant of Riagain (little king)."

The founder of the Munster O'Regan family, was also of Milesian origin, Cormac Cas, Prince of Bregia (Limerick and Louth counties), and son of Olliol Ollum, King of Munster A.D. 177, and Sabia, daughter of Con Kead Caha, King of Ireland A.D. 148. In the Third Century, Modhcorb, the son of Cormac Cas, controlled 10 tuaths in the Fermoy district of County Cork. The annalists in A.D. 1092, recorded a notable triumph of Mathghamhain O Riagain, King of Breagh, over the foreigners when he made prisoner Amalaoibh, son of Sitric, King of Dublin, and only released him on payment of of an enormous ransom, including the celebrated Sword of Carlus.

The O'Regans were also lords of Cill Mochuille of the tuath O'Cuscraidh, a small local kingdom. The tuath extended westward from Breighe Cobhunn to Ath Cross Malagha, and to the River Fiunshlon, near Kildorrery, 27 miles north of Cork city. No trace of the O'Regan sept can be found among the ruins of the minor church of Cill Mochuille and its graveyard. The O'Rehegans and O'Downeys were also part of the minor church.

Another O'Regan was chief of Ibh Ingarduil, one of eight tuaths. He joined with the O'Conways, lords of the tuath Ibh Maille MacHaire, into the one tuath O'Quain, likely in the llth century (see Book of Lismore AD 1460). The chief townland of Ibh Ingardhuil was Conbaidhb, so called from Fionn's hounds which drowned there. It lay along the River Blackwater in the Convamore district in northeast Cork, from Ballyhooly, four miles east of Fermoy, on the road to Mallow. Fermoy is about 17.25 miles northeast of Cork City. Cill Conain (now Kilcolman, Doneraile), the parish church of the tuath, was in the barony of Fermoy and parish of Ballyhooly. The O'Regan sept townland was Creagh, near Fermoy.

© Brian O'Regan, James O'Regan, 2000