A fulacht fia, the term used for a type of prehistoric cooking or processing site found in enormous numbers across Ireland, typically survives as a low horseshoe-shaped mound of heat-shattered stone and charred earth, the accumulated debris of repeated use over centuries. At Ballinguilly, even that much has gone. There is no visible surface trace.

What makes this absence quietly interesting is that the site did once leave a mark visible enough to be recorded. A 1943 Ordnance Survey six-inch map shows a mound at this location, which means that within living memory something was still there to be plotted. Fulachtaí fia, most commonly dated to the Bronze Age, are thought to have functioned by heating stones in a fire, dropping them into a water-filled trough to bring the water to a boil, and using that heat for cooking, hide-working, or possibly bathing. The broken, fire-cracked stones that result from this process are what builds the characteristic mound over time. That the mound at Ballinguilly has since disappeared, absorbed back into the marshy ground it occupied, is not unusual; wet, low-lying land is both the typical setting for these sites and the condition most likely to flatten or swallow the physical evidence.