A fulacht fia, the term used for these ancient outdoor cooking places, typically survives as a horseshoe-shaped mound of fire-cracked stone and charcoal built up over repeated use, where water was heated by dropping red-hot stones into a trough. At Lisnacon, that mound is gone.

The site was recorded in 1934 by Bowman, who noted a fulacht fiadh on land belonging to a Michael Healy. By the time the record was revisited, local knowledge had filled in what happened next: the low mound of burnt material, the accumulated debris of those ancient firings, had been levelled to make way for farm infrastructure. The slurry pit that replaced it is entirely ordinary; the archaeology beneath is not. Fulachtaí fia are found in their thousands across Ireland, dating mostly to the Bronze Age, and they cluster particularly around water sources and low-lying ground. Most were probably used for cooking, though some researchers have proposed other functions, including textile processing or bathing. Whatever its original purpose, the Lisnacon example is now known only through a brief mid-twentieth century reference and the memory of its disappearance.