To the untrained eye it reads as a slight rise in the ground, perhaps the result of field clearance or some forgotten bit of agricultural labour. In fact it is a fulacht fia, one of the most common yet persistently mysterious monument types in the Irish landscape, and this one stretches roughly 26 metres on its north-south axis and around 10 metres across, built almost entirely from heat-shattered stone and charred organic debris.

Fulachta fiadh (the plural form) are Bronze Age cooking sites, dating broadly from around 1500 to 500 BC, though some examples fall outside that range. The typical arrangement involved a trough dug into the ground, often near a water source, which would be filled and then heated by dropping fire-cracked stones into it until the water boiled. Once the stones were spent, they were tossed aside, and over generations of repeated use these discarded heaps of burnt material accumulated into the horseshoe or kidney-shaped mounds we see today. The one at Ballymountain follows that same logic: the spring beside it, now dry, would once have provided the water supply on which the whole process depended. Whether it served a travelling hunting party, a settled farming community, or some other purpose entirely remains an open question that archaeologists have debated for decades.