It measures roughly 13.5 metres north to south and 10.8 metres east to west, and it is composed almost entirely of burnt material, the cracked and fire-shattered stone that is the telltale signature of a fulacht fia. A stream runs to the west of the site, which is exactly where you would expect it.

A fulacht fia is a prehistoric cooking place, typically Bronze Age in origin, built around a simple but effective principle. Stones were heated in a fire and then dropped into a water-filled trough, bringing the water to a boil quickly enough to cook meat. The shattered, heat-spent stones were then discarded into a mound beside the trough, and over centuries of repeated use those mounds accumulated into the low, horseshoe-shaped or oval rises that survive across Ireland in their thousands. The proximity of a water source was not incidental; it was the whole point. The stream to the west of the Ardnageehy site would have fed the process directly, making this gentle slope a practical and well-chosen location. What looks like an unremarkable grassy hump in a field is, in that sense, the remains of a kitchen.