Ó Muirgheasa
Ó MUIRGHEASA—I—O Murrissa, O Morisa, O Morrissy, Morissy, Morrissey, Morrissy, &c, (Morris, Morrison); 'descendant of Muirgheas' (sea-choice); the name of a branch of the Ui Fiachrach who were formerly chiefs of a district on the southern shore of Sligo Bay, in the barony of Tireragh. It is highly probable that there were several other distinct families so called, as the name, both in the present form and as Ó Muirghis, is common in most parts of Ireland.
Alphabetical Index to Irish Surnames