The family name O'Regan, along with its cognates Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ri "sovereign, king" and the diminutive suffix -in; thus "the king's child" or "big king". The name was borne by two distinct families: one seated in Meath, the other in Thomond.
The O'Regans of Meath were a branch of the southern Ui Neill and one of the four Tribes of Tara. Before the Anglo-Norman invasion, they were lords of south Breagh and the north of present-day County Dublin. They took a leading part in the wars against the Danes. In the year 1029, Mathghamhain Ó Riagáin, king of Breagh, captured the king of Dublin, Amhlaoibh son of Sitric, releasing him only upon payment of an enormous ransom, which included the celebrated Sword of Carlus. The O'Regans were dispossessed soon after the invasion and dispersed through Ireland.
The O'Regans of Thomond are a Dalcassian family said to be descended from Riagán, son of Donncuan, brother of King Brian Boru.
People
Brian O'Regan (disambiguation), several people
Daniel O'Regan, New Zealand rugby league player
Danny O'Regan, American ice hockey player
Denis O'Regan, photographer
Dylan O'Regan, Irish American martial artist and submission grappler
Hana O'Regan, New Zealand Maori activist
J. Kevin O'Regan, psychologist interested in phenomenal consciousness
Kate O'Regan, South African lawyer and judge
Katherine O'Regan, New Zealand politician
Mark O'Regan, New Zealand judge
Michael O'Regan, co-founder of Research Machines
Patrick O'Regan, New Zealand politician and jurist
Rolland O'Regan, New Zealand politician and surgeon
Seamus O'Regan, Canadian politician and former broadcast journalist
Susan O'Regan, New Zealand politician
Tarik O'Regan, British composer
Tipene O'Regan, New Zealand politician and educator
Thomas O'Regan, Australian academic
Figures in the Catholic Church
Anthony O'Regan, Catholic bishop
Cyril O'Regan
Places
O'Regan's, Newfoundland and Labrador, a village in Newfoundland, Canada
References
