It measures roughly nine metres north to south and nearly sixteen metres east to west, and it is composed almost entirely of burnt material, the compacted debris of repeated high-temperature activity carried out here long ago. This is a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, particularly in Cork and Kerry. The typical interpretation is that a trough, dug into the ground and filled with water, was brought to the boil by dropping fire-heated stones into it. Those stones, once cracked and spent, were discarded to the side, and over years or centuries of use they accumulated into the characteristic low mound that survives today.

Fulachtaí fia, the plural form, are among the most common archaeological monument types on the Irish landscape, yet individual examples rarely attract much attention. Their dates generally fall within the Bronze Age, roughly 1500 to 500 BC, though some sites have produced earlier or later evidence. The exact purpose of the Coom example is unknown beyond what its form suggests. The burnt mound itself is the only record; no associated trough or timber structure has been documented here, which is not unusual, as such features are often only revealed through excavation. What survives above ground is simply the accumulated waste of a process carried out, probably many times over, by people who left almost nothing else behind.