This is a fulacht fia, a type of prehistoric cooking site found in their thousands across Ireland, typically Bronze Age in origin. The characteristic form, a crescent or horseshoe of fire-cracked stones dumped around a central trough, was produced by repeatedly heating stones in a fire and dropping them into water-filled pits to bring the water to a boil. The burnt and shattered stones, discarded after use, gradually built up into the mounds we see today.

The mound at Kilblaffer measures fourteen metres in length and eleven metres in width, rising to a height of one metre. Its opening, just over five metres wide, faces south-west, a common orientation seen at many such sites. Like most fulachta fiadh, it sits in low-lying, wet ground beside a stream, which would have provided the reliable water supply essential to whatever was happening here. Whether that was cooking, textile processing, or something else entirely remains a matter of ongoing debate among archaeologists; the simple efficiency of the hot-stone method has led some researchers to suggest these sites served a range of purposes beyond the purely culinary.