This particular example is known only because a farmer's plough disturbed the ground and brought up a spread of burnt material, the characteristic signature of these ancient features. There is no mound, no hollow, no surface trace of any kind remaining.

A fulacht fia typically consists of a horseshoe-shaped mound of fire-cracked stone built up around a trough, usually timber-lined and dug into the ground near a water source. The method, used from the Bronze Age onwards, involved heating stones in a fire and dropping them into the water-filled trough to bring it to a boil, most likely for cooking. Over time, the shattered, heat-fractured stone accumulates into the characteristic mound. In Ballyhoolahan Middle, whatever mound may once have existed has long since been levelled by agriculture, leaving only the scorched and fragmented material worked into the soil. That a spread of burnt stone was noticed at all suggests the site was significant enough to leave a detectable concentration even after repeated ploughing had dispersed it.