Meaning “Mountain of the hill slopes” Slieve Gullion is a mountain in the south of County Armagh in Northern Ireland. The mountain forms the core of the Ring of Gullion and stands as the highest point in the county with an elevation of 573 metres.
Slieve Gullion plays a prominent role in the mythology and history of the area and dominates the countryside around it. In favourable weather conditions offering magnificent views of as far away as Connacht and Dublin Bay.

Slieve Gullion is the eroded remains of a volcanic complex from 60 Million years ago and is surrounded by a ring dyke. Slieve Gullion has been shaped by glaciation and exhibits a classic ‘crag and tail’ glacial feature. The ‘tail’, composed of glacial deposits, points south.
Two cairns exist on top of the mountain on either side of the lake. The Northern one is a circular mound of stones approximately 40 feet in diameter while the Southern one is a large, well-preserved passage grave which is the highest yet discovered in Ireland.

Much of the surface of Slieve Gullion is covered with forest, heather, or stone. 612 hectares of dry heather on the mountain are designated a Special Area of Conservation, an Environmentally Sensitive Area, and an Area of Outstanding Natural Beauty (AONB).