Saint Ailill the First (also called Ailill the Elder, Ailill I, Ailiell, Ailild, Ailid, Alild, Ailillus, Alellus, Alildus, Oilill, Oileal, Oileald, Olildus, Olild, Elias, Eulalius, Helias; c. 460 – 13 January 526) was the Bishop of Armagh, Ireland from 513 to 13 January 526.
St. Ailill was a member of the Úi Bressail, a clan from the south side of Lough Neagh.
He was born in Drum Cád in the Barony of Oneilland East, County Armagh, like his successor and kinsman Ailill the Second.
Saint Ailill reigned as Bishop for 13 years.
The Annals of Ireland give the following obits- After his death St. Ailill was venerated as a saint and his feast was celebrated each 13 January, the day of his death.