Írgalach mac Conaing Cuirre (died 702), also called Írgalach ua Conaing, was a King of Brega from the Uí Chonaing sept of Cnogba (Knowth) of the Síl nÁedo Sláine branch of the southern Ui Neill.
Írgalach is listed as one of the guarantors of the Cáin Adomnáin ("Law of the Innocents") of Saint Adomnán arranged at the Synod of Birr in 697 where he is called King of Ciannachta.
His brother Congalach had been defeated by Niall mac Cernaig Sotal (died 701) of this sept at the Battle of Imlech Pich in 688.
The Fragmentary Annals of Ireland give the story of the curse the saint laid upon Irgalach for this act: "Cursed son," said he, "hardest and worst man of God's making, know that shortly you will be separated from your sovereignty, and you will go to Hell.
The Annals of Ulster record that Írgalach met his death the next year in 702 when invading Britons slew him on the coast opposite Inis Mac Nesáin (Ireland's Eye),[5] and the Fragmentary Annals link this with Adomnán's curse.