Mythical early invaders of Ireland according to the pseudo-history Lebor Gabála [Book of Invasions], named for the eponymous founder Nemed. They came third in succession after (1) Cesair and (2) the Partholonians, who preceded them by thirty years. Contemporary with the predatory Fomorians, arbitrarily cited here as the fourth invaders, the Nemedians preceded the Fir Bolg by eleven generations. Departing from Scythia in thirty-four ships, all but one lost when the party greedily pursued a tower of gold seen on the sea, the Nemedians wandered the world for a year and a half before landing in Ireland at a site and time not made specific. Least remarkable and romanticized of the Lebor Gabála invaders, the Nemedians built two royal fortresses (in Armagh and Antrim), cleared twelve plains, and formed four lakes. The chief druid of the Nemedians, Mide, the eponym of Meath, lit the first fire at Uisnech, which blazed for seven years and lit every chief's hearth in Ireland. Their singular distinction was in battling the hated Fomorians, three times successfully under Nemed's leadership and once catastrophically at Cnámross (to be distinguished from a Fenian battle at the same site). Subjugated by the Fomorians, the Nemedians were forced to pay a humiliating annual tribute at Mag Cétne each Samain. They sought vengeance by storming the Fomorian tower Tor Conaind on the heavily defended Tory Island (off Donegal). The Nemedian hero Fergus Lethderg killed the Fomorian champion Conand, but the Nemedians were slaughtered, only thirty surviving to be scattered about the world. Fergus Lethderg went north to Scotland; his son Britán Máel lived there until the arrival of the Picts, giving his name to the British and the island of Britain. Iarbonél migrated even further across northern Europe; his son Béothach founded a family which returned to Ireland, eleven generations later, as the Tuatha Dé Danann. The grandson of Nemed's son Starn, Semion led descendants known as Fir Bolg in ‘Greece’. Other notable Nemedians include Anind, the son of Nemed whose grave flooded Lough Ennell near Dún na Sciath, Co. Westmeath; Fergna, the fourth physician in Ireland; and Figma, the chief poet and historian.
A few commentators see faint echoes of actual Irish history in the Nemed, as they do not in the invasions of Cesair and the Partholonians. T. F. O'Rahilly's influential but still controversial Early Irish History and Mythology (Dublin, 1946) identified the Nemedians with the Érainn, a P-Celtic people.