|Author||Rev Patrick Woulfe|
|Source||Irish Names and Surnames|
Ó DONNGHAILE—I—O'Donnelly, Donnelly, Donneely; 'descendant of Donnghal' (brown-valour); the name of a distinguished family of Cinel Eoghain in Ulster who derive their name and descent from Donnghal, the fourth in descent from Domhnall, King of Aileach and brother of Niall Glúndubh, the eponymous ancestor of the O'Neills. The O'Donnellys were originally seated at Druim Lighean, now anglicised Drumleen, a short distance to the north of Lifford, Co. Donegal, but were afterwards expelled by the Cinel Conaill, when they settled at Ballydonnelly, now Castlecaulfield, to the west of Dungannon. It was at Ballydonnelly that the celebrated Shane O'Neill was fostered by the O'Donnellys. O'Donnelly was hereditary marshal of O'Neill's forces; and Donnell O'Donelly, who accompanied Hugh O'Neill to Kinsale as 'captain of one hundred men,' fought bravely until he and all his men were slain. Ballydonnelly was granted by James I to Sir Toby Caulfield, ancestor of the Earl of Charlemont. The family is now very numerous in Ulster. There were also families of the name in Sligo and Cork. The former were a branch of the Ui Fiachrach, and were seated at Dun Ui Chobhthaigh, now anglicised Doonycoy, in the parish of Templeboy. The latter were a branch of the Corca Laoighdhe, and were seated near Dunmanway.
Alphabetical Index to Irish Surnames