It is a fulacht fia, a type of site found in considerable numbers across Ireland, and one of the more quietly puzzling features of the prehistoric landscape. The term refers to a horseshoe-shaped mound of fire-cracked stone and charcoal-rich earth, typically found near water and interpreted as the remains of an ancient cooking place. The standard theory holds that stones were heated in a fire, then dropped into a water-filled trough to bring it to a boil, the discarded cracked stones accumulating into the mound over repeated use. Some archaeologists have proposed alternative functions, including textile processing or bathing, though none of these explanations has been settled conclusively.

By the mid-twentieth century, the site at Ballinguilly had already receded far enough into the landscape that it appeared on a 1943 Ordnance Survey six-inch map simply as a mound, with no further designation. The marshy, waterlogged ground that likely made the location useful in the first place has since worked against any easy investigation, and the surrounding area is reported as heavily overgrown and inaccessible. It is the kind of site that endures precisely because the land around it has never been worth clearing.