It is a fulacht fia, a type of site found in enormous numbers throughout the Irish countryside, characterised by a spread of fire-cracked stone and charred material that accumulated, over repeated use, into a distinctive horseshoe-shaped mound. At Knocknamona, that spread measures roughly 9.6 metres east to west and 12.4 metres north to south, sitting quietly in pasture with nothing to mark it from a distance except a slight rise in the ground.

Fulachtaí fia, the plural form, are among the most common prehistoric monuments in Ireland, yet their purpose remains a matter of genuine debate. The conventional interpretation is that they were outdoor cooking sites, where stones were heated in a fire and then dropped into a trough of water to bring it to the boil, with the shattered, spent stones discarded to the sides. Other theories propose uses ranging from textile processing to bathing. Whatever their function, they were in use predominantly during the Bronze Age, roughly 1500 to 500 BC, though some sites have produced earlier or later dates. The Knocknamona example was recorded by Bowman in 1934, making it one of the earlier documented sites in the region, noted at a time when systematic archaeological fieldwork in rural Cork was far from routine.