The mound is modest in scale, measuring roughly 5.3 metres northeast to southwest and 7.5 metres northwest to southeast, rising only about a third of a metre from the ground. That unassuming profile is typical of a fulacht fia, a form of prehistoric cooking site found in considerable numbers across Ireland, usually identified by the characteristic dark, charcoal-rich material left behind after repeated use of heated stones to boil water in a trough.

What gives this particular site its quiet interest is the layering of time visible in the landscape. A fulacht fia, likely dating to the Bronze Age, has been absorbed into the northeast angle of a later earthwork enclosure, suggesting the site was either already a feature in the ground when the ringwork was constructed, or that its material was simply incorporated without ceremony into whatever came next. A second fulacht fia lies a short distance to the west, which is not unusual; these sites often cluster in valley bottoms near water sources, and the undulating ground at the base of a south-facing hill here would have offered both shelter and proximity to the drainage patterns that made such cooking sites practical. The relationship between the two mounds and the possible ringwork at Greenan leaves open questions about sequence and intention that the surface alone cannot answer.