Ó Muimhneacháin
Ó MUIMHNEACHÁIN—I—O Moyneghane, O Myneghane, Mynahan, Minahan, Moynahan, Moynihan, Moynan, &c., Munster; 'descendant of Muimhneachán' (Munsterman); the name (1) of a family of the Ui Fiachrach in Erris, Co. Mayo, in which county it is still extant, but sometimes translated Munster; and (2) a very common surname in Kerry and West Cork, where it is almost universally anglicised Moynihan. See Ó Muimhnigh.
Alphabetical Index to Irish Surnames