Ó Deargáin
Ó DEARGÁIN—I—O Dargane, O Dergane, O Darigan, Dargan, Dergan, Dorgan, Dorrigan; 'descendant of Deargán' (diminutive of dearg, red); an old surname in Westmeath, Offaly and Cork. In the last-named county, it is now anglicised Dorgan, which is not very correct.
Alphabetical Index to Irish Surnames