It is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, and this particular example is a well-preserved horseshoe shape, roughly fourteen and a half metres long, nearly fourteen metres wide, and rising about eighty centimetres above the surrounding pasture. The opening of the horseshoe, eight metres across, faces south-west. The mound itself is composed of burnt and fire-cracked stone, the accumulated debris of repeated use over what may have been centuries.

Fulachtaí fia are among the most common archaeological monuments in the Irish landscape, with thousands recorded across the country, the majority dating to the Bronze Age, roughly 2000 to 500 BC. The typical arrangement involved a timber-lined or stone-lined trough sunk into the ground near a water source, a hearth for heating stones, and a working area nearby. Stones were heated in the fire and then dropped into water in the trough to bring it rapidly to the boil. The spent, shattered stones were then discarded to the sides, building up over time into exactly the kind of horseshoe-shaped mound visible at Meenroe. Debates about their precise function continue among archaeologists; cooking is the long-standing interpretation, though uses ranging from bathing to textile processing have also been proposed. The crescent shape of the mound, open on one side, is characteristic and reflects where the trough would originally have sat.