It measures roughly eleven metres east to west and nine metres north to south, rising only half a metre above the surrounding ground. The shape is horseshoe-like, opening to the east, and a small stream runs nearby in that same direction. That orientation is not accidental. This is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, typically Bronze Age in date, where stones were heated in fire and then dropped into a water-filled trough to bring it to the boil. The burnt and shattered stones, discarded after use and built up over many cycles, are what form the characteristic mound.

The site has not come through the centuries entirely undisturbed. The landowner noted that the mound was partially levelled at some point, with stones deposited along the western arc rather than left in their original arrangement. Despite this interference, the structure retains its essential form, and a small patch in the northwest arm, roughly forty by thirty centimetres, still exposes the dark burnt material beneath the turf. More striking still is that a second possible fulacht fia lies approximately twenty-five metres to the east, suggesting this particular patch of boggy ground near Carhoomeengar was used repeatedly, or perhaps simultaneously, for the same purpose. Whether this reflects a favoured spot along a reliable water source, or some other pattern in the local prehistoric landscape, is not recorded.