It measures 11.5 metres long and 7.5 metres wide, and it sits just four metres from a second, near-identical feature. Both were simply left in the ground.

The site came to light in 1988 during construction of the Bruff-Mallow gas pipeline, when the removal of topsoil exposed the distinctive burnt mound. The feature belongs to a class of monument known as a fulacht fia, one of the most common prehistoric site types in Ireland. The basic principle is straightforward: a trough, usually timber-lined or stone-lined, was filled with water and heated by dropping fire-cracked stones into it. The stones, once spent, were raked out and piled to the side, forming the characteristic horseshoe or crescent mound of blackened, shattered rock that survives for millennia in the soil. The function of these sites is debated; cooking is the most widely accepted explanation, though brewing, hide-working, and bathing have all been proposed. What is unusual at Rathgoggan is not the monument type itself, which numbers in the thousands across Ireland, but the proximity of two examples sitting almost side by side in open pasture, neither of them subsequently investigated.