Donnelly

Irish: reduced Anglicized form of Gaelic Ó Donnghaile ‘descendant of Donnghal’, a personal name composed of the elements donn ‘brown-haired man’ or ‘chieftain’ + gal ‘valor’. It is claimed that most bearers of this surname in Donegal descend from Donnghal O’Neill, 17th in descent from Niall of the Nine Hostages; there were also other families of the same name in Sligo and Cork.