In fact, they are stepping over a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish landscape. These kidney-shaped mounds, typically composed of fire-cracked stone and charcoal-darkened soil, are the accumulated debris of repeated episodes of water-heating, most likely for cooking, though bathing, textile processing, and brewing have all been proposed. They date predominantly to the Bronze Age, making this quiet feature in a County Galway woodland several thousand years old.

This particular example sits roughly five metres east of the Coole River, a proximity that is entirely typical of the type, since a reliable water source was essential to the process. The mound measures 11.5 metres north to south and 5.5 metres east to west, rising to a modest maximum height of 0.4 metres, low enough to be easily overlooked. Its central hollow, the depression left by the trough around which the heating activity took place, opens to the west. Some stone visible around the eastern half of the hollow may represent original revetment, the lining or edging material that once held the structure together, though it is also possible that this material has slipped from an estate wall that cuts across the eastern end of the site. That wall is a reminder of the demesne's later history: Coole Park was for centuries the estate of the Gregory family and became famous in the early twentieth century as the country retreat of Lady Augusta Gregory, a central figure in the Irish Literary Revival.

The mound lies directly on the route of the nature trail, which crosses its western half, so a visitor who knows what to look for will find it without any difficulty. The central hollow and the low curving profile of the mound are the key features to notice; the kidney shape, though partially obscured by the trail and the nearby wall, remains legible on the ground.