It measures roughly twenty metres north to south, ten metres east to west, and rises only about seventy centimetres above the surrounding ground. What fills that mound, though, is what makes it interesting: burnt material, the accumulated debris of a fulacht fia, one of Ireland's most numerous and least understood prehistoric monument types.

A fulacht fia is essentially the remains of an ancient outdoor cooking or processing site. The typical setup involved a trough, often lined with timber or stone, filled with water that was then heated by dropping fire-cracked stones into it. Those stones, once spent and shattered by repeated heating and cooling, were discarded into a mound nearby. Over centuries, these dumps of scorched and broken stone built up into the low, horseshoe-shaped or oval mounds that survive across the Irish countryside in considerable numbers. The site at Lisbealad follows this familiar pattern, sitting close to a river, which would have provided a ready water supply. Bronze Age communities are most commonly associated with fulachta fiadh, though the monuments have been difficult to date precisely and debate about their precise function continues among archaeologists.