To a passing eye it might seem like nothing much, but it is almost certainly the remains of a fulacht fia, one of the most commonly found yet least fully understood monument types in the Irish landscape.

A fulacht fia is essentially a prehistoric cooking or processing site. The typical arrangement involves a trough, often timber-lined or cut into the ground, which would be filled with water. Stones were heated in a nearby fire and then dropped into the trough to bring the water to a boil. Over time, the cracked and discarded stones accumulated into a mound, usually horseshoe-shaped, which is what survives today. The proximity to a water source is characteristic; these sites are almost always found close to streams, rivers, or boggy ground, and the site at Kilmacoom fits that pattern precisely. The spread of burnt material noted here, recorded through personal communication from M. McCarthy and J. O'Shaughnessy and published in the Archaeological Inventory of County Cork in 2000, indicates a site of some scale. The fact that it lies in tillage, meaning it has been subject to ploughing over the years, suggests the original mound may be considerably more dispersed than it once was, though the burnt stone scatter remains visible.

Fulachtaí fia date most commonly to the Bronze Age, roughly 1500 to 500 BC, though some examples have been shown through excavation to span earlier or later periods. Their precise function has been debated; cooking is the most widely accepted explanation, but proposals have also included use for brewing, textile processing, or bathing. Most, when excavated, produce little in the way of artefacts, which adds to the difficulty of interpreting them with any confidence.