It is roughly nine metres across and barely half a metre high, domed in profile, with an elongated hollow scooped into its western side. That hollow is the telling detail. This is a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, and the hollow marks where a trough once held water.

Fulachtaí fia (the plural form) are among the most frequently recorded prehistoric monuments in Ireland, typically dating to the Bronze Age, though some examples fall outside that range. The standard interpretation is that stones were heated in a nearby fire, then dropped into a water-filled trough to bring it to boiling point, cooking meat or perhaps serving other purposes such as bathing or textile production. Over time, the discarded cracked and fire-shattered stones accumulated into the characteristic horseshoe-shaped or rounded mound that survives today. The hollow at Ballyremon Commons corresponds to where the trough would have been, either cut into the ground or formed by a wooden or stone-lined pit. The heathland setting is typical; these sites tend to cluster near low-lying or marshy ground where water was reliably available, and a gentle slope would have assisted natural drainage toward a convenient source.