Cairnech is the name of several Irish saints.
1. One of this name (written Caernach) appears in the Four Masters among the deaths under A.D. 779 (rather 784), as son of Suibhne, and prior of Armagh. In the Annals of Ulster, A.D. 783, he is called " Caernach mac Suibhne equonimus Ardmachae" i.e. house-steward of Armagh.
2. Commemorated March 28, was the son of Saran and Pompa (or Bebona), and was born after A.D. 450. His brothers were St. Berchan and St. Ronan, and his monastery was probably at Cruachan Ligean, on Lough Foyle, near Lifford. He must have died about A.D. 530, and thus could scarcely have been associated with St. Patrick in revising and purifying the Irish laws.
4. Of Tuilen-commemorated May 16-is probably the St. Carnocus ("Episc. Culdeus") of June 15 of Camerarius. He flourished about A.D. 450, and was the son or grandson of Ceredig. Choosing the religious life, he went to Ireland, where he co-operated with St. Patrick. He. returned to Britain, but eventually died in Ireland. Colgan cannot decide whether this Cairnech or the one preceding is the Carnechus Moel who wrote the Acts of his master, St. Ciaran. This Cairnech is said to have come from Cornwall to join St. Patrick, and to have helped him to compile the Brehon laws. He, therefore, lived in the 5th century. His burial-place is said to be at Dulane, in Meath. The Welsh represent him as the son of Ceretic, and say that he was born in Cardigan.