Mac An Ultaigh
Mac an ULTAIGH—VII—MacAnulty, MacKnulty, MacNulty, Nulty; 'son of the Ulidian' (or native of East Ulster, Irish 'Ultach'); the name of a Donegal family, who are probably a branch of the O'Dunlevys. (See Ó Duinnshléibhe and Mac Dhuinnshléibhe). It is now common in Mayo and Meath. In the latter county, it is always anglicised Nulty.
Alphabetical Index to Irish Surnames