It rises only 0.61 metres at its highest point and spreads roughly eleven metres in each direction, looking more like a gentle swelling of the ground than anything deliberate. But its shape and position mark it out as a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland, typically consisting of a horseshoe-shaped burnt mound of heat-shattered stone built up beside a water trough. The trough, usually timber-lined or stone-lined and filled with water, was heated by dropping fire-cracked stones into it until the contents boiled. What is quietly notable about this particular mound, and several others nearby in the same townland, is that no trough area is currently visible at any of them.

The site sits approximately forty metres south of another recorded fulacht fia in the same area, and the concentration of these monuments across Tylagh is itself significant. As Michael Connolly observed in his 2008 doctoral thesis on the prehistoric settlement of the Lee Valley, the mounds in this part of the townland consistently afford open views southward and south-westward over the Lee Valley. Whether that orientation was purely practical, related to water sources or movement routes through the landscape, or carried some other meaning for the communities who built and used these sites, is not something the archaeology alone can answer. The clustering of fulachtaí fia here suggests sustained prehistoric activity in the valley over a considerable period, with this mound forming one node in a wider pattern rather than an isolated curiosity.