Roughly 22 metres long and 9 metres wide, it is covered in turf and gives almost nothing away. What lies beneath, however, is the accumulated debris of prehistoric cooking, a fulacht fia, one of the most common yet least understood monument types in the Irish landscape.

A fulacht fia, sometimes called a burnt mound, is the remains of an ancient outdoor cooking site, typically Bronze Age in date, though examples range across several millennia. The usual arrangement involved a trough, often timber-lined or stone-lined, filled with water and heated by dropping fire-cracked stones into it. Those stones, once spent, were raked out and discarded nearby, and it is that growing heap of shattered, fire-blackened stone that forms the mound we see today. The proximity to a stream is entirely typical; a reliable water source was essential to the process, and the vast majority of fulachta fiadh in Ireland are found close to running water or boggy ground. The Parkgarriff example follows this pattern precisely, sitting on the southern bank of a stream, where generations of use built up the spread of burnt material that survives today.