To a passing eye it reads as nothing more than a slight rise in a field, but it marks the site of a fulacht fia, one of the most common yet quietly puzzling monument types in the Irish countryside.

Fulachtaí fia are ancient cooking or processing sites, typically identified by their characteristic horseshoe-shaped mounds of fire-cracked stone. The usual method involved heating stones in a fire and dropping them into a water-filled trough to bring the water to boiling point, a technique that explains both the proximity to a water source and the distinctive burnt, fragmented character of the debris. They occur in their thousands across Ireland, often close to streams or marshy ground, and date broadly from the Bronze Age, roughly 2000 to 500 BC, though some examples may be earlier or later. The Glenleigh site follows this pattern closely: the stream nearby would have provided the necessary water supply, and the south-east-facing slope would have offered reasonable shelter and drainage.