Irish surname search
(Mac)Nulth
The derivation of many Irish surnames is open to doubt, but there is none about that of MacNulty: in Irish it is Mac an Ultaigh, I.e. son of the Ulsterman. An older anglicized form of the name, now rare, is MacAnulty. The MacNultys belong to-day as they have done since the inception of surnames, to north-west Ulster - to Donegal, which claims to be the most Irish part of Ireland. As might be expected from the location of this sept they were overshadowed by the O'Donnells, sometimes in association with them, as in the battle of Desertcreagh in 1281 (a MacNulty was among the "distinguished slain" there), sometimes against them as on the occasion in 1431 when the O'Donnells are recorded by the Four Masters as making a predatory expedition against the MacNultys of Tirhugh (Co. Donegal). From Derry, on the border of Co. Donegal, came Frank Joseph MacNulty (1872-1926), an American labour leader, whose father Owen MacNulty was a veteran of the Civil War.
The name is also found in Co. Meath but usually it is shorn of its prefix Mac there. I presume these Nultys are an offshoot of the Donegal MacNultys. Bernard MacNulty (d. 1892), friend of John Boyle O'Reilly, was the founder of the first branch of the Fenian Brotherhood in the U.S.A.