Padraig Mac Giolla-Domhnaigh

Mehaffy—This name is one of the numerous anglicised forms of the Scottish sept name Mac Dhuibh-shithe who were located in Colonsay for generations up to the beginning of the Seventeenth Century, when the clan was scattered, many passing over into Ulster. The name is variously anglicised, namely: Mac Duffie, Duffie, McAfee, McFee, McPhee, McPhie McFie, M'Haffie, M'Haffy, M'Covvie, M'Covie, M'Guffie, M'Guffog, McAffer, and M'Caffer; the four latter forms being found in Galloway. The most of the forms given are found in Ulster, and considering the number of the sept, we find under the various forms, it must number a large sept.

Alphabetical Index of Anglicised Surnames in Ireland

See also Woulfe’s Irish Names and Surnames
and O'Hart's Irish Pedigrees