This radial-stone cairn, roughly 3.5 metres in diameter and no more than 0.4 metres tall, is not the sort of monument that announces itself. Its presence is easy to underestimate until you consider how deliberately it was put together, and by whom.

What makes Knocknakilla particularly interesting is not any single monument but the concentration of prehistoric activity in one compact area. The cairn sits just seven metres from a five-stone circle and a pair of standing stones, all clustered together on the same shelf of bogland. Five-stone circles are a type of stone circle found predominantly in Cork and Kerry, characterised by five uprights with a recumbent, or horizontal, stone typically placed opposite the tallest pair. The proximity of the cairn to the circle and the standing stones suggests this was a place of sustained ceremonial or funerary significance, returned to and elaborated upon over time. The site was catalogued by Seán Ó Nualláin in 1984 as part of his systematic work on stone circles in the south of Ireland, and it has carried the protection of a preservation order since 1941.