Ó Dubhghaill
Ó DUBHGHAILL—II—O Dogaill, O Dowill, O Dowell, O Doole, O'Doyle, Doyle, Dowell, Doole, &c.; 'descendant of Dubhghall' (the black foreigner); a very common Irish surname, doubtless of Danish origin. It is found in all parts of Ireland, but is most frequent in the maritime counties of Leinster and Munster, and in the neighbourhood of the old Danish settlements.
Alphabetical Index to Irish Surnames