Roughly seven metres north to south, four to five metres east to west, and rising about a metre in height, it sits quietly against the natural gradient of the hillside, covered in moss and rushes, looking for all the world like an unremarkable hump in a wet field.

What it actually represents is a fulacht fiadh, or burnt mound, a type of prehistoric cooking or processing site found in considerable numbers across Ireland. The basic principle involves heating stones in a fire, then dropping them into a water-filled trough to bring the water rapidly to the boil. The cracked and shattered stones, useless after a single heating, were discarded, and over repeated use they accumulated into exactly the kind of low, horseshoe-shaped or oval mound seen here. The charcoal-rich matrix binding the burnt sandstone at Killacorraun is characteristic of this process, the residue of many fires built and abandoned over what may have been generations of use. These sites are most commonly dated to the Bronze Age, though some were in use earlier or later. They tend to cluster near water and low-lying or boggy ground, which makes the location here, on land only recently reclaimed from bog, entirely typical.