The Irish surname McIlhenney is an anglicized form of the Gaelic name Mac Giolla Choinnigh meaning “son of the servant of (Saint) Coinneach or Canice.” St. Canice, who came from Dromachose in County Derry, was a pupil of St. Finnian at Clonard. He founded a monastery at Aghabre in Ossory circa 577, and also had a foundation in County Kilkenny. He died in Ossory around the year 600. The Mac Giolla Chainnigh sept, i.e. "sons of the followers of St. Canice" were of the Cenel Eoghain group, a collective clan name for tribes descended from Eoghan, son of Niall of the Nine Hostages, the 5th Century High King of Ireland, who were chiefly located in Counties Derry, Tyrone and Donegal. The first recorded spelling of the family name is shown to be that of McElhinney of Londonderry, which was dated circa 1600, in the "Late Tudor Fiants (Fiant Litterae Patents)." Today the name is found exclusively in counties Derry and Donegal.