A fulacht fia, which is broadly understood to be a prehistoric cooking or heating site, once rose here as a kidney-shaped mound, its form recorded on a 1937 Ordnance Survey six-inch map with the careful hachuring used to indicate earthworks. By around 1978, it had been levelled as part of drainage works. What remains is a spread of burnt material, the scorched stone and charcoal residue that fulachtaí fia almost always leave behind, and which is often all that survives of sites that were in use as far back as the Bronze Age.

Fulachtaí fia are among the most numerous prehistoric monument types in Ireland, particularly in Munster, and the Coolowen example fits a familiar pattern. They typically consist of a horseshoe or kidney-shaped mound of heat-shattered stone, built up over repeated use beside a water source. The prevailing theory holds that stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, though what exactly the hot water was used for, whether cooking, bathing, hide-working, or something else entirely, remains a matter of ongoing discussion among archaeologists. The Coolowen site was documented by Walsh in 1985, and its presence on the earlier OS map suggests it was still a recognisable earthwork feature into the mid-twentieth century before drainage changed the landscape around it.