A cairn, in the Irish prehistoric tradition, is typically a mound of heaped stones built over a burial or used as a landscape marker, sometimes dating back thousands of years. This one measures roughly sixteen metres east to west and twelve metres north to south, rising to no more than a metre at its highest point, with a large boulder, about a metre long and seventy centimetres wide, sitting at its eastern edge. Without that boulder, and without what the map-makers once wrote above it, it could easily pass for nothing more than a slightly uneven field.

What makes this site peculiar is its paper trail, or rather the near absence of one. The mound appears on the 1907 edition of the Ordnance Survey six-inch map, labelled in gothic lettering as a "Carn", the older anglicised spelling that signals the surveyors recognised something worth noting. But it does not appear on earlier editions of the same map series, which means either it was overlooked in previous surveys or its identification as an ancient feature came late. The site itself occupies a rise towards the bottom of a north-west-facing slope, a position that feels deliberate in the way that prehistoric monument placement often does, though the ground today gives little away. Grass and scrub have long since softened whatever original form the stones once held.