It has been suggested that McCool, derived from Mac Giolla Comhghaill, meaning ‘son of the devotee of St Comhghal’ or from Mac Comhghaill, is a distinct sept from the Raphoe area of County Donegal.
They were one of the seven powerful septs supporting O’Neill. The surname McDaid is virtually exclusive to northwest Ireland. The name is most numerous in County Donegal where over half the McDaids ...