Congal Cennfhota (‘longheaded’) (d. 674), son of Dúnchad and overking of Ulaid, belonged to the dynasty of Dál Fiatach. His father and uncle, Dúnchad and Máel-Cobo, held the overkingship of Ulaid in turn, marking a revival of Dál Fiatach fortunes after the slaying in 637 of Congal Clóen (qv) of the Cruthin dynasty of Dál nAraide. In 647 Congal slew his uncle, presumably in an effort to secure the kingship for himself. In the event, Máel-Cobo's son Blathmac (qv) succeeded, and enjoyed a lengthy and relatively peaceful reign till he died in 670.
His cousin's death presented Congal with a long-awaited opportunity to establish himself as overking. It seems likely that he had the support of the Uí Néill dynasty of Síl nÁedo Sláine, as his daughter Conchend was married to Fínshnechtae Fledach (qv), the future king of Tara. Nonetheless, Congal Cennfhota was not destined to reign for long: he was slain in 674 by Bécc Bairrche (qv), son of his cousin Blathmac. The latter ultimately secured his position within Dál Fiatach by marrying Conchend (perhaps not till after Fínshnechtae's death, although this is not clear), and in time attained the provincial kingship. The immediate beneficiary of Congal's death, however, was Fergus son of Áedán, a member of the Cruthin dynasty of Uí Echach Cobo, who dominated Ulaid for some eighteen years. Congal Cennfhota left a son, Cú Roí, and a grandson, Démmán, but the later kings of Dál Fiatach came from the line of Bécc Bairrche.