Lorcán mac Cathail (blinded 864) was a King of Uisnech and Mide of the Clann Cholmáin. Lorcán ruled in as King of Mide from 862–864. His exact dynastic affiliations are unknown. The death of a certain Cathal mac Conchobair is mentioned in the annals in 843. If this was his father he may have been the grandson of the High King Conchobar mac Donnchada (died 833). Upon the death of Máel Ruanaid mac Donnchada Midi of Mide in 843, a succession dispute broke out. Whether the mention of Cathals's death in that year by the annals implies that Cathal died as part of this dispute or was the heir (he would have been senior in the clan at that time) and his death led to the dispute, is not mentioned. Lorcán did succeed to the throne himself in 862 possibly as senior heir.