McDonough
The Gaelic name, which is most frequently spelled in English as McDonough, is MacDonnchadha, the son of Donnchadh. Donnchadh is the Irish name for Dennis, a rather common Christian name in ancient Ireland. This surname is also anglicized as McDonogh and McDonagh.
As often happens in the case of Irish surnames derived from Christian names, we find the name MacDonnchadha adopted by two distinct families of ancient lineage: The McDonough’s of Connacht and McDonoughs of Munster.
The Connacht clan were of the same Celtic stock as the MacDemotts and through them were kinsmen of the O’Connors. For centuries they were one of the most powerful clans of Western Ireland. The McDonough’s territory was located in Counties Sligo and Roscommon. They were the chiefs of Tirerril and Corran and their main stronghold was Ballymote. It was under the patronage of these McDonoughs that the “Book of Ballymote” was complied. Descendants of the family are still numerous in Connacht.
The Munster McDonoughs were of branch of famous McCarthy Clan. These families were the chiefs of Duhallow in County Cork and their ancestral seat was the Castle of Kanturk. Following the repeated disasters of Elnizbethan, Cromwellian and Williamite wars they like their kinsmen, the McCarthys, lost their lands and influence. So complete was this ruthless confiscation that few representatives of this once great family now survive even in their native County Cork.
Deprived of their lands, the McDonoughs found scope for their abilities in Europe. Between 1690 and 1770 A.D., no fewer than forty-two McDonoughs served as brilliant officers in the Dillion regiment of the Irish Brigade. Three McDonough brothers distinguished themselves at the Battle of Cremona, while another officer helped to win the day for the French army at the Battle of Fontenoy.