It measures roughly nine metres east to west and just half a metre in height, covered in grass and unremarkable at a distance. What makes it worth pausing over is what it represents: a fulacht fia, a type of prehistoric cooking site found across Ireland and Britain in the thousands, typically dating to the Bronze Age. The usual interpretation is that these sites functioned as outdoor cooking places where water was heated by dropping fire-cracked stones into a trough; the shattered, heat-spent stones were then piled to the sides, gradually forming the characteristic horseshoe or kidney-shaped mound that survives today.

At Pollnacroaghy, the mound is composed of stone fragments set in charcoal-rich soil, a combination entirely consistent with that repeated cycle of heating and discarding. On its northern side, between what might be thought of as the two arms of the kidney shape, there is a shallow C-shaped hollow measuring roughly 2.6 metres east to west and 2 metres north to south. This depression is thought to indicate the original position of the trough, the functional centre of the whole operation, where water would have been held and brought to temperature. The site occupies a level strip of ground about ten metres north of the Dalgan River, a meandering westward-flowing stream, with the valley slope rising just a few metres behind it. The choice of location follows a pattern common to fulachtaí fia generally: low-lying ground near a reliable water source, practical for the work the site was designed to do.