 The Fernmag, or Fer Fernmaighe, is an area around Lough Ooney, aka Lock Uaithne near Smithborough in the barony of Dartry, Co. Monaghan.Immigration to south-eastern Monaghan brought the territorial name along with it, being preserved in the name of the barony of Farney.The genealogies given for the Fernmag claim they descend from Fergusa, the son of Nadsluaig, who was one of the sons of Cairpre Dam Argait.