It is not much to look at, perhaps a metre high, roughly D-shaped, and measuring around seven metres north to south. But this is a fulacht fia, one of the most numerous and yet least understood monument types in the Irish landscape, and the broken stones spilling from its surface and into the streambed tell a story of repeated, deliberate heating and sudden cooling.

A fulacht fia is, in essence, the debris of an ancient cooking or processing site. The typical method involved heating stones in a fire until they were near-cracking point, then plunging them into a water-filled trough to bring the liquid rapidly to the boil. The stones, fractured by thermal shock, were discarded after use and gradually accumulated into the crescent or horseshoe-shaped mounds that survive across Ireland in their thousands. Most date to the Bronze Age, roughly 1500 to 500 BC, though some sites show evidence of much longer use. What makes the Lackaroe site quietly unusual is that a second, near-identical mound lies only two metres away on the opposite bank of the same stream. The pairing suggests this small watercourse was a focal point for repeated activity, with the stream serving both as a water source and, perhaps, as a boundary between two distinct episodes or groups of use.