The mound measures roughly eight metres across and stands about 2.3 metres high, an irregular hump that might easily be dismissed as a natural rise in the ground. It is, in all likelihood, a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish archaeological record.

Fulachtaí fia, found in their thousands across Ireland, are generally interpreted as prehistoric cooking sites, though brewing, hide-working, and bathing have all been proposed as alternative or complementary uses. The typical arrangement involves a horseshoe-shaped mound of fire-cracked stones alongside a timber-lined trough dug into the ground. The method is straightforward: stones were heated in a fire, then dropped into a water-filled trough to bring it to a boil. Over repeated use, the shattered, heat-spent stones accumulated into the mound that survives today. At Dunmanus, possible trough areas have been identified to the north and east of the mound, hinting at that familiar layout beneath the surface. The burnt material visible under the grass is consistent with exactly this kind of sustained, repeated heating and discarding of stone. Most fulachtaí fia date to the Bronze Age, roughly 1500 to 500 BC, though some have earlier or later origins.

The site sits in low-lying boggy ground, the kind of wet, marginal terrain that these monuments favour, partly because a reliable water source was essential to their function, and partly because such ground was less likely to be disturbed by later agriculture. That same dampness has helped preserve what lies below the turf.