It is the kind of feature that a casual walker might step over without a second thought, yet the material it is made of tells a more compelling story: heat-shattered stones and charcoal-enriched soil, the signature residue of a fulacht fia.

A fulacht fia is a Bronze Age cooking place, typically consisting of a trough dug into the ground, a hearth for heating stones, and a mound of the discarded, cracked stones that were used to boil water by being dropped into the trough when heated. They are among the most common prehistoric monuments in Ireland, yet each one represents repeated, organised activity on the same spot, sometimes over generations. This particular example measures nine metres on its north-west to south-east axis and 6.5 metres across, with the characteristic opening, 3.1 metres wide, facing south-west. What makes Derrymihin especially notable is not any single mound in isolation but the clustering of three of them in close proximity. Two further fulachtaí fia lie within roughly 60 metres to the south-east and 30 metres to the south-south-west, suggesting that this boggy slope was a place people returned to repeatedly, across what may have been a considerable span of time. Whether that reflects seasonal activity, a particularly reliable water source, or something else entirely remains an open question.