Partially grass-covered and roughly circular, it measures just over four metres at its widest and rises to less than a metre in height. What makes it quietly remarkable is not any single feature but the fact that it is not alone: this cairn is one of nine clustered in the same area of rough hill pasture, with the nearest neighbour sitting only about twelve metres to the east.

Cairns of this kind are among the most enduring marks left on the Irish landscape, typically understood as prehistoric burial monuments, though their precise function and date can vary considerably. They consist of deliberately piled stones, sometimes covering a burial chamber beneath, and are often found in upland or marginal terrain where the land was never intensively farmed and so the monuments were never cleared away. At Ballynafullia, traces of kerbing, the ring of stones set around the cairn's perimeter to contain the mound, are still visible along the western and north-eastern arcs of this particular example. The grouping of nine cairns in a single locality suggests this hillside carried real significance to the communities who built here, perhaps as a place of burial, commemoration, or territorial marking, though the archaeology does not yet resolve exactly which.