Set on the northern summit of Slieve Gullion this is the highest surviving passage tomb in the British Isles. It is known locally as 'the Calliagh Berra's House'. Unusually for this type of tomb, the walls are not made with orthostats but with the sort of stones a farmer might use to build a field wall.
There is a smaller dolmen built during the Bronze Age, on the southern summit of the mountain. Excavations in 1961 uncovered two small rectangular stone graves or cists within the cairn, one of which contained a cremation burial and the remains of a decorated pot known as a food vessel.