Conall Grant mac Cernaig (died 718) was a King of Brega of the Uí Chernaig sept of Lagore of the Síl nÁedo Sláine.
[4] Conall is among the guarantors of the Cáin Adomnáin (Law of Innocents) proclaimed at the Synod of Birr in 697 where he is given the title King of Deiscirt Breg or southern Brega.
[7] In 714, his nephew Fogartach was deposed from the kingship and went to Britain possibly by the high king Fergal mac Máele Dúin (died 722) of the Cenél nEógain.
[8] Conall may have acquired the rule of Brega and in 715 he was responsible for the assassination of Murchad Midi, the King of Uisnech from the Clann Cholmáin, possibly the deputy of Fergal.
[10] Then, in 718 Conall fought the Battle of Cenannas (near Kells) and defeated and slew Amalgaid of Cnogba and his brother Fergal, along with their allies, Gormgal mac Áedo of Síl nDlúthaig and Tuathal Ua Fáelchon of Clann Cholmáin Bicc.