What looks like a gentle rise in the ground, roughly nine to ten metres across and less than a metre high, is in fact a fulacht fia, a type of prehistoric cooking or processing site found widely across Ireland. The basic principle involved heating stones in a fire, then dropping them into a water-filled trough to bring the water rapidly to the boil. Over time, the fire-cracked stones were discarded into a characteristic horseshoe-shaped or rounded mound beside the trough. Here, where the sod has been worn away in places, dense concentrations of small limestone fragments are visible within a matrix of dark grey soil, the compacted debris of repeated use.

The site sits at the boundary between open grassland and woodland at Keelhilla, around two hundred metres east of the foot of the east-facing cliffs of Slieve Carran, a limestone escarpment in the Burren. Damp ground lies immediately to the west, and roughly forty to forty-five metres further into the hazel wood there is a spring associated with a holy well. That proximity to water is typical of fulacht fia sites, which required a reliable source nearby. The mound is most pronounced on its eastern and south-eastern side, and lower and more spread out to the west, which may indicate where the trough once sat. A hawthorn tree has rooted into the north-eastern edge of the mound, and a second hawthorn stands close to the southern side, beside a large boulder that rests on the mound's edge. The boulder appears to be a remnant of a ruined field wall running roughly east to west, which skirts the south-eastern and southern edge of the mound, suggesting that later agricultural activity pressed close against, and partly over, the prehistoric feature without entirely obscuring it.