It is not much to look at: a spread of blackened, fire-cracked stone about fourteen and a half metres across, with a hollow worn into its south-western side where material has been dug away over the years. Yet this modest feature is a fulacht fia, one of the most common and least understood monument types in the Irish archaeological landscape, and this particular example is one of at least ten recorded in the same townland alone.

A fulacht fia, sometimes called a burnt mound, is the accumulated debris of a prehistoric cooking method. The typical setup involved a trough filled with water, heated by dropping fire-cracked stones into it repeatedly; once used, the shattered, heat-exhausted stones were raked out and piled to the side. Over centuries and repeated use, these spoil heaps built into the crescent or horseshoe shapes that survive today. They cluster near water sources, which is consistent with this example sitting close to a spring. The Ballybahallagh mounds were noted by a researcher named Bowman in 1934, who documented ten such features in the townland, suggesting this part of north Cork was used with some intensity during the Bronze Age period when fulachta fiadh were most commonly in use. The north-eastern side of the mound has since been clipped by two field fences, and burnt material has actually been incorporated into their construction, meaning the boundaries of modern agricultural land are partly built from the wreckage of a much older activity.