At roughly eight metres long, six metres wide, and only twenty centimetres high, the mound is easy to miss, and easier still to dismiss. What it represents, however, is a cooking technology used across Ireland for thousands of years, one so common in the archaeological record that it has been called the most frequently encountered prehistoric monument on the island.

A fulacht fia is, at its simplest, the debris left behind by repeated open-air cooking. The typical method involved heating stones in a fire, dropping them into a water-filled trough to bring it rapidly to a boil, and using that heat to cook meat or other food. The stones, cracked and blackened by thermal shock, were discarded into a horseshoe-shaped mound around the trough, and it is those accumulations of fire-shattered material that survive in the landscape today. The site at Tooreenclassagh was one of three such mounds recorded on what was then M. O'Mahony's land, first noted by Bowman in 1934. By around 1957, local accounts suggest the mound had been levelled, most likely in the course of agricultural improvement as the surrounding pasture was brought back into use. That partial reclamation explains both the mound's modest height and the slight ambiguity of its edges.