These horseshoe-shaped mounds, found in their thousands across the country, are the remains of ancient cooking or processing sites, typically Bronze Age in date, where stones were heated in fire and then dropped into water-filled troughs to bring them to the boil. The stones, fractured by repeated heating and cooling, were raked aside after use and piled up over time into the distinctive crescent shape that survives today. They tend to cluster near wetlands and streams, which provided the necessary water supply, and the name itself is sometimes translated loosely as "cooking place of the Fianna", though the legendary association tells us more about later folklore than prehistoric reality.

The Poulgorm example sits within a county that has an unusually dense concentration of these sites, particularly across its low-lying boggy terrain where waterlogged conditions have helped preserve both the mounds and, in some cases, the wooden troughs beneath them. Bronze Age communities across Ireland used these installations over a period roughly spanning from around 1800 to 500 BC, and while cooking remains the most widely accepted explanation for their function, researchers have also proposed uses ranging from bathing and textile processing to brewing. The ambiguity is part of what makes fulachta fia so quietly compelling: they are everywhere underfoot, yet their everyday purpose remains a matter of reasonable academic debate.