It is easy to walk past something like this without quite registering what you are looking at: a few stones, some upright, some fallen, partly covered by two displaced roof slabs. But the detail that draws the eye, once you know to look, is a set of cupmarks carved into the most easterly roofstone. These shallow circular depressions, ground into the rock surface by prehistoric hands, appear on megalithic monuments across Ireland and Britain, though their precise meaning remains unresolved. They are one of the oldest surviving marks of human intent in the landscape.

This is a wedge tomb, a type of megalithic burial monument built predominantly during the late Neolithic and into the Bronze Age, roughly between 4,000 and 2,500 years ago. Wedge tombs are the most numerous of Ireland's megalithic tomb types and are concentrated heavily in the west of the country. They take their name from their characteristic shape: the gallery is typically wider and higher at one end, tapering toward the other. At Cloontreem, the gallery is modest in scale, roughly 2.4 metres long and 1.25 metres wide at its south-western end, and is aligned on a north-east to south-west axis. Of the side stones, two remain erect on the south-east side, while the north-west side retains one upright and one fallen stone. The whole structure sits in rough mountain pasture, the kind of terrain that has, in its very inhospitability to improvement, preserved these monuments where lowland examples were long ago cleared away.