It measures roughly thirteen metres north to south and fourteen metres east to west, and at some point somebody dug into its southern end and piled the extracted material to the north. Five stone slabs lie across the middle of the excavated area, two of them visibly scorched, resting on a grey, ash-like deposit. It is the kind of feature that rewards a second look, because what seems at first like a heap of field clearance turns out to be something far older and more deliberate.

This is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, particularly from the Bronze Age. The typical arrangement involved a trough dug into waterlogged ground, a nearby fire for heating stones, and a method of dropping those heated stones into the water-filled trough to bring it to a boil. The cracked and spent stones were then discarded to the side, building up over repeated use into the horseshoe-shaped or spread mounds that survive today. The grey ash deposit and the burnt slabs at Ardnageehy fit this pattern closely. The site sits roughly seventy metres south-west of a ringfort, a later form of enclosed settlement dating generally to the early medieval period, which suggests this particular patch of ground was in use across more than one era. Whether the proximity is coincidental or reflects some continuity of occupation in a locally favourable spot, the marshy ground that made the fulacht fia practical in the first place may well have made the surrounding land attractive for settlement long afterwards.