Ó Fionnáin
Ó FIONNÁIN—I—O Finane, O Fenane, O Fanane, O'Finan, Finan, Finnan, Fannon, (Fannin, Fanning); 'descendant of Fionnán' (diminutive of Fionn, fair); also written Ó Fionáin; the name of a Mayo family who were chiefs of Coolcarney, a district which embraced the parishes of Kilgarvan and Attymas, but now long dispersed; also, according to MacFirbis, of a family of Cinel Eoghain in Ulster.
Alphabetical Index to Irish Surnames