Imposing peak (1,893 feet), 5 miles SW of Newry, 8 miles W of Dundalk, Co. Armagh. One of the best-known promontories in all of Ireland, dominating the Gap of the North, gateway from Ulster to the south, widely celebrated in Irish tradition. On the south slope lies a cruciform passage-tomb locally called Calliagh Birra's House (see CAILLEACH BHÉIRE). Eponym of the mountain is Cuilenn, a lord of the sídh in Fenian narrative. Different versions of one story portray Fionn mac Cumhaill weakened or diminished by his adventures here. In a representative version he bathes in a lake on Sliab Cuilinn and is transformed into a feeble old man. After Fionn's warriors lay siege to the sídh, Cuilenn comes forth with a golden cup whose contents not only restore the hero but give him and a companion supernatural knowledge. Folklorist Michael J. Murphy commemorated the mountain in two widely known books, At Slieve Gullion's Foot (Dundalk, 1940) and Mountain Year (Belfast, 1964, 1987).