Ardgal (d. 970), son of Matudán and overking of Ulaid 950–70, was of the Dál Fiatach dynasty. He succeeded his father Matudán son of Áed, overking of Ulaid 937–50, who was slain by the Uí Echach. During the reign of Ardgal, the Ulaid faced a threat from the Northern Uí Néill; in 962 they defeated and slew Flaithbertach son of Conchobar, king of Ailech, when the latter plundered Condere (Connor, Co. Antrim, later a diocesan see). In 970 Ardgal allied with some neighbouring vikings and plundered Connor, ‘leaving a great many beheaded there’. He was killed the same year at the battle of Cell Móna (Kilmona, Co. Westmeath), fighting in the army of the Cenél nÉogain king of Tara, Domnall Ua Néill (qv), against Domnall son of Congalach Cnogba (qv). Ardgal's sons Eochaid (d. 1004), Gilla-Comgaill (d. 1005), and Máel-ruanaid (d. 1007) all later became kings of Ulster. He was initially succeeded by his uncle Niall (d. 971).
AU; AFM; Bk Leinster, i, 194; vi, 1451; O'Brien, Corpus geneal. Hib., 322; NHI, ix, 132