Eóganacht Locha Léin or Ui Caipre Luachra were a branch of the ruling Eoganachta of Munster. Their territory was in Iarmuman or West Munster. Luachair (Lúachra) is the old name of a large district on the borders of Co Cork, Kerry and Limerick. Cairbre of Sliobh Luachra was on the Cork-Kerry border; Éoganacht Locha Lein is around the Lakes of Killarney.
The ancestor of this branch was Caipre Luachra mac Cuirc, son of Corc mac Luigthig (or Conall Corc mac Lugdach,the founder of Cashel) by Mungfionn daughter of Feredach, King of the Picts of Scotland. Caipre Luachra was a sixth generation descendant of Éogan Mór, ancestor of the Eoganachta. Caibre went west over Luachair Deadhaid (Slieveloughra) to found the lands of his dynasty
Ruling septs of Éoganacht Locha Lein included Úa Cathail, Úa Flainn, Úa Muircheartaigh or Moriarty, and Úa Cerbaill. By the 12th century the Úa Donnchadha (O'Donoghues, Cenél Laegaire of Éoganacht Raithleann), leaving Éoganacht Raithleann of Cork, had conquered and settled Éoganacht Locha Lein.
The Loch Lein branch had a free client relationship with the kings of Cashel and were often called kings of Íarlúachair or kings of Loch Lein in the annals. The Loch Lein branch rarely provided kings of Cashel and were not part of the inner circle of Eoganachta. They included: