Cináed (d. 851), son of Conaing and king of Cianachta and north Brega, belonged to the Uí Chonaing lineage of Síl nÁedo Sláine, an Uí Néill dynasty based at Cnogba (Knowth), Co. Meath. His father, Conaing, died (849) as king of Brega. Cináed had at least two brothers; Dúnchad, the elder, was sub-king to Conaing and predeceased his father, dying (832) as king of Cianachta. The younger, Flann, later reigned as king of Brega.
It seems that Cináed succeeded to the kingship of northern Brega after his father's death. Against a background of Norse incursions into the midlands, Cináed may well have secured a marriage-alliance with Amlaíb (qv) (Óláfr) son of Gofraid, king of Dublin – the latter's wife was the daughter of one Cináed. Certainly, Cináed son of Conaing allied himself with a viking warband and then (850) revolted against his overlord, the king of Tara, Máel-Sechnaill (qv) son of Máel-ruanaid of Clann Cholmáin. Having raided a number of the ecclesiastical settlements of Mide including Trevet, Cináed and his allies attacked and levelled the crannóg of Lagore, seat of the rival Síl nÁedo Sláine lineage of Clann Chernaig Shotail, then in alliance with Máel-Sechnaill. The revolt was crushed and Cináed was captured in what appear to have been treacherous circumstances. In spite of guarantees from the abbot of Armagh, Cináed was executed by Máel-Sechnaill and the king of Lagore by being drowned in a ‘dirty stream’, identified by later annalists as the River Nanny in Co. Meath. He was succeeded in the kingship of north Brega by his brother Flann.