That distinction is not accidental. The dark, scorched earth and fragments of heat-shattered red stone still visible within it are the unmistakable traces of a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically beside water sources. The basic principle involved heating stones in a fire and dropping them into a water-filled trough to bring it to the boil; the cracked, reddened stones were then discarded into a pile, which over time formed the characteristic horseshoe-shaped or oval mound that survives in the landscape long after everything else has gone.

This particular example was recorded in 1985 as part of the Castleisland District Archaeological Survey, which noted that the monument had been levelled in 1981, just four years before its documentation. Despite that disturbance, the mound retained enough physical presence to be clearly identifiable. It measures roughly eleven metres from north to south and just over twelve metres from east to west, with swampy ground pressing in from the west-south-west and a dyke and field fence marking its eastern edge. The proximity to marshy land is consistent with what is known of fulachtaí fia more broadly; water was not incidental to their function but central to it, and the wetland setting at Knockawinna fits a pattern repeated at prehistoric cooking sites across the country.