The mound stretches nearly seventeen metres in length and eight metres wide, rising just under a metre at its highest point, with the ground sloping gently upward from west to east. Along its eastern edge, there are possible traces of a stone revetment, a retaining wall of sorts, suggesting that the mound was at some point given a more deliberate edge or boundary.

Fulachtaí fia are found in their thousands across Ireland, typically dating to the Bronze Age, and they are generally understood as the debris left behind by a particular method of cooking or heating water. The process involved heating stones in a fire until they were intensely hot, then dropping them into a water-filled trough to bring the water to a boil. The stones, cracked and useless after the thermal shock, were discarded into a pile beside the trough, and over repeated use these discarded stones accumulated into the horseshoe-shaped or oval mounds that survive today. The burnt, fragmented stone gives such mounds their characteristic dark, crumbly appearance. Whether the troughs were used for cooking meat, bathing, textile processing, or some combination of purposes remains a matter of genuine archaeological debate. The example at Lyroe, now absorbed into agricultural land, is a modest but well-preserved instance of this widespread Bronze Age practice.