It measures roughly 8.5 metres across and just 0.6 metres high, the kind of feature that a walker might cross without registering as anything other than a natural rise in the ground.

This is a cairn, a burial monument of the type typically associated with the Bronze Age, in which stones were heaped over the remains of the dead, sometimes covering a cist grave or cremated remains beneath. The Ballynabrocky example has been slightly robbed out or disturbed on its southern side, a common fate for such structures, whose loose stone made them convenient quarries for field walls and farm buildings over the centuries. It sits on a slight hummock, which may itself have influenced the original choice of location, since prehistoric communities often selected elevated or subtly prominent ground for funerary monuments, places that held meaning within the wider landscape even when that meaning is now lost to us.