Killarga or Killargue (Irish: Cill Fhearga) is a small village in County Leitrim, Ireland. Killarga is an ancient place of pilgrimage and was attached to a religious settlement, Cill Fhearga, which according to the Annals of the Four Masters was founded by a holy woman, St Fearga, as early as the 6th century. There is a holy well named Tobar Mhuire, a 19th-century lime kiln on the way into it, a (ancient Irish sweat house) and other historical ruins in the area. Nearby is O'Donnell's Rock which is named after Aodh Rua Ó Dónaill.