Slieve Gullion Passage Tomb, dramatically situated on the southern end of the Slieve Gullion summit ridge at an altitude of over 570m, this is the highest surviving passage tomb in Ulster with stunning views over the surrounding countryside. It consists of a circular cairn some 30m in diameter and up to 4m high, with a kerb of massive, but undecorated, stones around the perimeter. A slight indentation on the south-west marks the entrance to a short, lintelled, passage which leads to the octagonal, originally corbelled, chamber.
The earliest documented investigation of Slieve Gullion Passage Tomb dates to 1789, when the chamber was opened by locals searching for the old lady or Cailleach Beara, but only a few human bones were found. Not surprisingly, excavation in 1961 revealed that the chamber had been badly disturbed and the only small finds were a few pieces of worked flint, a single scraper and an arrowhead. Two of the stone basins, commonly found in passage tombs, were also discovered below modern fill in the chamber and a third (now housed in Armagh County Museum) was recovered from the outer end of the passage.
Excavation of Slieve Gullion Passage Tomb also revealed that a small cairn of stones, about 12m in diameter, had subsequently been added to the northern side of the tomb. Although no burials or structural features were uncovered by the excavation, it seems reasonable to interpret this as a Bronze Age addition. A small round cairn on the northern end of the summit ridge was also excavated in 1961 revealing two small cist graves and fragments of distinctive Early Bronze Age pottery.
Slieve Gullion dominates the landscape of the area and plays a central role in many folk tales. Several link Finn McCool with the mountain, and one wellknown story involves the Cailleach Beara, who entices Finn to swim in the magical lake on the summit of the mountain, only for him to emerge as an old and weak man.