It measures roughly twenty-five metres in each direction, and beneath its grassy skin lies a spread of burnt and fire-cracked stone that tells a much older story.

This is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, particularly in low-lying or waterlogged ground close to a reliable water source. The typical arrangement involved a trough dug into the ground, often timber-lined, which was filled with water. Stones were heated in a nearby fire, then dropped into the trough to bring the water to a boil. The repeated heating and rapid cooling caused the stones to fracture, and the discarded material accumulated over time into the characteristic horseshoe-shaped or oval mound that survives today. At Garrynagearagh, the proximity to the stream fits this pattern precisely. Such sites date broadly to the Bronze Age, though some may have been used across several periods, and they are frequently interpreted as communal cooking or food-processing sites, though other uses, including bathing or industrial processes, have also been proposed by researchers over the years.