It is roughly semicircular, opens towards the south-west, and stands less than a metre high. What makes it remarkable is what it is made of: burnt and fire-cracked stone, the residue of repeated prehistoric cooking. This is a fulacht fia, a type of ancient outdoor cooking site found in considerable numbers across Ireland, typically dated to the Bronze Age. The standard interpretation is that stones were heated in a fire, then dropped into a water-filled trough to bring the water to a boil, and the cracked, discarded stones accumulated over time into exactly the kind of horseshoe-shaped mound seen here.

The mound at Moanroe measures twenty-three metres in length, sixteen and a half metres in width, and just under a metre in height, which places it at a substantial size for this type of monument. Its position is telling: it sits on the north-eastern side of what is now a dried-up pond. That detail matters, because fulachtaí fia are almost always found close to a water source, whether a stream, a spring, or a natural hollow that would have held water. The pond beside this one has long since dried out, but its presence in the landscape explains why someone chose this particular spot, presumably centuries or millennia ago, to carry out whatever activity, cooking, brewing, bathing, or processing of materials, left behind this quiet crescent of charred stone.