²Hencken, H. O'Neill. "A Long Cairn at Creevykeel, Co. Sligo." The Journal of the Royal Society of Antiquaries of Ireland 2 (1939): 96-97.
According to Anthony Weir, the Irish name for the site (Caisleán Bhaoisgin) may derive from the mountain behind Creevykeel, called (in transliteration) "Benwiskin," which seems to mean something like "Make-you-Mad Mountain."  Baois = folly, rage, madness, impropriety, lust, silliness...The suffix -gin in Irish is cognate with gen- in Greek (genesis, gene, etc. meaning producer or producing), so the mountain—or more likely the cairn—was that which made people a bit mad (as in faerie enchantment).