It is sod-covered, dotted with hawthorn and blackthorn, and worn enough to suggest something long undisturbed. Locally, it has always been called a fairy hill, and local tradition holds that it contains a souterrain, an underground stone-lined passage or chamber of the kind built in early medieval Ireland, often for storage or refuge. Whether the mound is artificial, natural, or some combination of the two has never been conclusively settled.

The mound runs roughly west-northwest to east-southeast, measuring around 29 metres along its length and about 17 metres across, rising to approximately 2 metres at its highest point. Its profile is noticeably asymmetrical: the southern side drops away in a steep, well-defined slope, while the northern side slumps more gradually. The whole structure has an irregular, somewhat dilapidated look. It appears to be composed largely of fine gravel and sand, which gives weight to the possibility that it is a natural glacial feature, though the association with a souterrain suggests human activity at some point in its history. A heap of dredging upcast from the nearby river has been deposited against its southern edge, adding another layer to an already ambiguous form. The Mannin River itself flows out of Island Lake roughly 230 metres to the south, and the surrounding ground is low-lying bog and pasture, the kind of wet, marginal landscape where such features tend to survive precisely because no one has had much reason to disturb them.