It measures roughly twenty metres north to south and fifteen metres east to west, and to the casual eye it could pass for nothing at all. But the combination of heat-shattered stones and charcoal-enriched soil is the unmistakable signature of a burnt mound, one of the most common yet least understood monument types in the Irish archaeological record.

Burnt mounds are the accumulated debris of a process that involved heating stones in a fire, then dropping them into a water-filled trough to bring it rapidly to the boil. The stones crack under the thermal shock and are discarded in a heap, which over repeated use grows into the low, dark spreads that survive across the Irish landscape in their thousands. What exactly these sites were for remains genuinely contested; cooking, bathing, textile processing, and communal gathering have all been proposed. They belong broadly to the Bronze Age, though the type persisted across a long span of prehistory. The example at Coolymurraghue is not alone in its immediate vicinity: another possible burnt mound lies approximately one hundred and twenty metres to the south-east, which suggests either repeated activity in a favoured location or a broader pattern of use across this particular stretch of ground.