A souterrain is an underground stone-lined passage or chamber, typically built during the early medieval period in Ireland, used variously for storage, refuge, or ventilation of associated settlements. This one was recorded on a six-inch Ordnance Survey map produced in 1940, marked with enough confidence to be plotted, yet when surveyors later examined the ground, there was nothing to see. No depression, no collapsed lintel, no tell-tale hollow in the grass.

The site sits roughly ten metres south-east of a cairn, a mound of heaped stones that often marks a prehistoric burial. That proximity is not unusual in the Irish landscape, where features from entirely different periods frequently end up as neighbours, each accumulating its own layer of record while the ground above them carries on as ordinary farmland. What makes this particular souterrain quietly curious is the gap between its cartographic existence and its physical absence. The 1940 map is the sole witness, and whatever the surveyors of that era observed or inferred has since been swallowed entirely by the soil and the turf.