The Irish and Scottish surname Mahaffey is an anglicized version of the Gaelic name Mac Dhuibhshithe meaning " the dark haired peace-maker ". The Mahaffey's are part of the MacFie Clan in Scotland although the name originated in Ireland, The name is predominantley found in County Donegal in the north west of Ireland. Today there are approximately 8,000 people in the United States with the last name Mahaffey.