It is, by any measure, a modest lump in the landscape, easy to overlook and easy to mistake for a natural feature. But it is a fulacht fia, one of the most common prehistoric monument types found across Ireland, and its quiet presence in the grass carries a considerable weight of years.

Fulachtaí fia (the plural form) are the remains of ancient cooking sites, typically Bronze Age in date, though the exact practices carried out at them have been the subject of long debate among archaeologists. The standard interpretation is that stones were heated in a fire, then dropped into a water-filled trough to bring it to a boil, and the cracked and shattered residue was piled to one side over time, eventually forming the characteristic horseshoe or oval mound of burnt material that survives today. The Knocknagoun example is a circular mound rather than the more typical horseshoe shape, which is itself a small point of interest. What makes the site additionally notable is its proximity to a standing stone, the remains of which lie immediately to the south-east. The pairing of a fulacht fia with a standing stone is not unheard of, and may reflect something about how prehistoric communities organised their landscape, though the precise relationship between the two monuments at this location is not known.