This is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically Bronze Age in origin. The usual interpretation is that such sites were used to heat water by dropping fire-cracked stones into a trough, then using that hot water to cook meat. Over time, the shattered stone accumulated into the distinctive crescent-shaped mound that survives today, and it is this mound, roughly 13 metres north to south and 12 metres east to west, rising to about 1.1 metres in height, that remains visible at Ballynacourty.

What makes this particular site quietly remarkable is its density of company. Some 175 metres to the west lies another fulacht fia, and a further example sits just 2.5 metres to the south, an unusually tight clustering that suggests this valley, close to the northern bank of a small stream and opening out towards the sea a short distance to the south-west, was a place of repeated or sustained activity over time. The mound itself is well defined along its southern and western edges, while elsewhere the boundary is indicated by a subtle shift in vegetation rather than any obvious earthwork. One feature that catches the eye is a patch of nettle growth, which marks the position of the original trough area. Nettles tend to thrive where soil has been disturbed or enriched, and their presence here is a small, living indicator of where the ancient working activity was concentrated.