It measures about eighteen metres north to south and twenty metres east to west, rising only some sixty centimetres above the surrounding ground. To a passing eye it might read as a natural feature, a slight rise in the field, but its composition gives it away entirely.

The mound is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland, typically dating to the Bronze Age. The working principle was straightforward: stones were heated in a fire and then dropped into a water-filled trough, bringing the water to a boil. The repeated heating and sudden cooling caused the stones to crack and crumble, and the discarded fragments accumulated over time into exactly the kind of horseshoe-shaped or rounded mound visible here at Kilberrihert. The proximity to the River Allow is entirely typical; fulachtaí fia are almost always found near a reliable water source, since a steady supply was essential to the whole process. Thousands of these sites have been identified across Ireland, making them one of the most common archaeological monument types in the country, yet each one represents an accumulation of repeated, deliberate activity across what may have been generations of use.