What makes it quietly peculiar is not the mound itself but what is no longer there: a decorated stone, reputed to have come from this passage tomb, which now sits in the National Museum of Ireland rather than in the earth where it presumably spent several millennia. Passage tombs are a form of megalithic monument in which a stone-lined corridor leads to a burial chamber at the centre of a mound; decoration on their stones, typically spirals, lozenges, and other abstract motifs carved into the rock, is relatively rare and marks a site as something more than a simple burial place.

The mound at Tornant measures 18.6 metres in diameter and stands 1.6 metres high, positioned on the north-eastern edge of an east-west ridge with wide views across the surrounding terrain. The landscape around it undulates in a way characteristic of the Wicklow uplands, and the ridge placement would have given the tomb a commanding, deliberate relationship with the skyline. A partly artificial, flat-bottomed gully sits immediately to the west of the mound, and a shallow fosse, a type of ditched enclosure feature, runs along the south-east. There is also a hollow at the top of the mound, roughly 1.5 metres across and half a metre deep, of the kind that often results from centuries of informal digging or natural settling over a disturbed interior. The decorated stone associated with the site is referenced in studies by Price (1953) and Shee-Twohig (1981), the latter a key scholar of megalithic art in Ireland, though the word "reputed" in the historical record is a reminder that the stone's exact provenance was never definitively confirmed.