It is a fulacht fia, one of the most common yet least understood monument types in the Irish landscape. The name, loosely translated as "cooking place of the deer," refers to Bronze Age sites where stones were heated in fire and then dropped into a water-filled trough to bring it to the boil, most likely for cooking. The process left behind a distinctive horseshoe-shaped mound of heat-shattered, blackened stone, and that is precisely what remains here at Gortlahard.

The mound is well-defined despite its age, measuring ten metres in both directions and standing around 0.8 metres high. Its opening, about 1.8 metres wide, faces north-west, and it sits on the south-east bank of a small stream, which would have provided the essential water supply for the trough. The stream itself has done some of the work of exposure over time, cutting into the eastern arm of the mound and revealing the burnt material within. This kind of natural erosion, though it can cause damage, occasionally offers a useful cross-section that confirms what the surface shape alone suggests.