The baronial and dynastic family of McCaughan derived its lineage from the indigenous nobility (nobiles majores) of the ancient Kingdom of Galloway, through Eachain, the progenitor of the MacEachains. Eachain, a prince of the Pictish race of Scotland and Dal-n-Araidhe in the Counties of Antrim and Down, Ireland, was the son of Iriel Glumore, the twenty-third King of Ulster and his wife Locetna, the daughter of Eochy, King of the Picts in Alban, now Scotland.
Dal-n-Araidhe, or as it is now commonly recorded Dalaraidhe, was the last Pictish Kingdom in Ireland. Geographically, Dalaraidhe extended northward from the base line drawn through Carlingford Lough and the town of Newry in County Down, with the Bann River to Lough Neagh and west, and the Irish Sea and North Channel on the east, and the Glenavel River on the north.
As the name implies, this part of Ireland was named after Araidhe, King of the Picts (Rex Piotorum) who was slain about 248 A.D. by the Heremonians or Scots as they advanced north into Dalriada, the next kingdom north and from whence they, or their representatives, passed over into the, now Kingdom of Scotland.