It measures twenty metres long, twenty metres wide, and just over half a metre high, and it is composed almost entirely of burnt and fire-cracked stone. That detail is the key to understanding what it is: a fulacht fia, the remains of a prehistoric outdoor cooking site, where stones were heated in a fire and then dropped into a water-filled trough to bring it to a boil. The discarded, shattered stones accumulated over repeated use into exactly this kind of crescent-shaped mound, which is one of the most recognisable archaeological forms in the Irish landscape.

Fulachtaí fia are found in their thousands across Ireland, typically close to water sources, which explains the stream immediately to the west of this example. They are generally dated to the Bronze Age, though some have produced dates ranging from the Neolithic through to the early medieval period. What makes the Killeenleigh site quietly notable is that it does not stand alone. A second fulacht fia lies approximately thirty metres to the north-west, suggesting that this particular stretch of ground beside the stream saw repeated or prolonged use, or perhaps activity by more than one group across different periods. Paired or clustered fulachtaí fia are known elsewhere in Ireland, and their proximity to one another raises questions that the archaeology alone cannot fully answer, about whether they were contemporary, sequential, or served different functions.