At first glance it looks like little more than a gentle hump in the pasture, half a metre at its highest point and roughly fourteen metres across. But the material beneath the turf tells a different story: the mound is composed of burnt stone, the accumulated debris of repeated heating and quenching over what may have been centuries of use.

This is a fulacht fia, a type of prehistoric cooking site found in very large numbers across Ireland, almost always in damp or waterlogged ground. The typical method involved heating stones in a fire, then dropping them into a water-filled trough to bring it to the boil. The stones shatter with the thermal shock and become useless after a single use, so they are discarded nearby, building up over time into the characteristic horseshoe-shaped mounds that survive today. At Coolacurn, the trough survives as a depression measuring 3.6 metres long and 2.5 metres wide, opening toward the north-east. A drain cuts through the monument on a roughly east-to-west alignment, likely introduced at some later point to manage the persistently wet ground. The site was brought to wider attention by Dr C. Cunniffe.