O%27regan Family History
O%27regan Name Meaning
Irish: Anglicized form of Gaelic Ó Riagain ‘descendant of Riagán’, a personal name of uncertain origin, perhaps akin to ríodhgach ‘impulsive’, ‘furious’. There are two families of this surname, in Meath and Munster; traditionally they both claim descent from a nephew of Brian Boru called Riagán (see Regan).
Source: Dictionary of American Family Names ©2013, Oxford University Press