Gillies, Gillis, Gillison

Padraig Mac Giolla-Domhnaigh

Gillies, Gillis, Gillison—These three names are three of the many anglicised forms of the name Mac Giolla-Iosa, the other anglicised forms being McAleece, McAlish, McLeish, McLees Leishman, Leish, Lees and Leece; the two latter forms being met with in the Isle of Man and on the mainland in the North-West of England. The name in Scotland and in Ulster is of the same origin. It is descended from the McPhersons, through one of that clan called Gilli-Iosa Mac Pherson, and for centuries the sept was known as the "Sliochd Gille-Iosa."

Alphabetical Index of Anglicised Surnames in Ireland

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