Reid
Reid—The name is the anglicised form of Mulderrig (O'Maoildeirg) in N.W. Ulster, known as "The Red-haired Reids." See Rutledge and Reddington. O'Mulderrig is an old County Donegal sept.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees