The larger of the pair measures seventeen metres long, sixteen metres wide, and less than a metre high, a subdued lump in the landscape that most people would walk past without a second glance. The smaller mound immediately to its northwest is lower in footprint but rises higher, and the material it contains may have been shifted there from the main mound at some point, leaving the relationship between the two slightly unresolved.

What these mounds represent is one of the most common yet quietly puzzling monument types in the Irish archaeological record. A fulacht fia, sometimes called a burnt mound, is the accumulated debris of repeated high-temperature cooking or heating activity, typically dated to the Bronze Age, though some sites were in use across several periods. The standard interpretation involves heating stones in a fire, dropping them into a water-filled trough to bring the water rapidly to the boil, then discarding the shattered, heat-spent stone to the side. Over time, and over many episodes of use, the waste builds into a characteristic horseshoe or subcircular mound, dark with charcoal and studded with fragmented rock. Why people chose boggy ground near water makes obvious practical sense; the trough could be dug into waterlogged earth and would fill naturally. What was actually being cooked, or whether the troughs served other purposes entirely, remains a matter of ongoing debate among archaeologists.