It is easy to miss: the mound rises only about 0.8 metres at its highest, stretches some twenty-two metres in length and thirteen and a half metres across, and its eastern opening gives it the shape of a broad horseshoe pressed gently into the ground. What it represents, however, is a feature found across Ireland in the hundreds, and still not entirely understood.

This is a fulacht fia, sometimes written fulacht fiadh, a term referring to a prehistoric cooking or processing site. The characteristic form is a mound of fire-cracked stones and charred material, the debris left behind after repeated heating of stones in a fire and their transfer into a water-filled trough, which would have brought the water rapidly to a boil. The method is ancient and efficient. The Glenacarney example was recorded by Bowman in 1934 and noted as lying on land belonging to J. Broderick. The site fits the classic profile: the horseshoe shape, the burnt mound material, and the proximity to a water source in the form of the nearby well, since access to water was essential to whatever activities these sites were used for. Whether that was cooking meat, brewing, bathing, or some combination of uses remains a matter of ongoing discussion among archaeologists.