Eochaid Mugmedón was a legendary Irish king. According to medieval Irish legend and historical tradition, Eochaid was a High King of Ireland, best known as the father of Niall of the Nine Hostages and ancestor of the Uí Néill and Connachta dynasties. He is not mentioned in the list of kings of Tara in the Baile Chuind (The Ecstasy of Conn), but is included in the synthetic lists of High Kings in the Lebor Gabála Érenn, the Irish annals, Geoffrey Keating's history, and the Laud Synchronisms.