It looks, at a glance, like a natural rise in the ground. It is not. Beneath the turf lies a spread of burnt and fire-cracked stone, the accumulated debris of a fulacht fia, one of the most common yet still somewhat puzzling monument types in the Irish archaeological landscape. A fulacht fia is thought to be a prehistoric cooking site, where stones were heated in a fire and dropped into a water-filled trough to bring it to the boil. The discarded, shattered stones were piled beside the trough over repeated use, gradually forming the horseshoe-shaped or rounded mounds that survive in their thousands across Ireland.

This particular example was recorded by a Broker in 1937, who described it as round, roughly four spades across, which he estimated at about twenty-two feet, and standing four feet high. Those dimensions suggest a well-preserved and fairly substantial deposit. What makes Knocknageeha a little more interesting than a single mound in a field is that a second fulacht fia lies approximately ninety metres to the south. The pairing, and their shared proximity to a stream, which would have supplied the water essential to the cooking process, points to a stretch of ground that was returned to, or perhaps continuously used, over some period. Whether the two sites represent the same community working the same landscape across generations, or something more episodic, is not something the surface evidence can settle.