It is roughly 36 metres across at its widest, rises only about a metre and a half, and is covered with large outcropping boulders. What makes it quietly extraordinary is the question of what it actually is: a natural glacial feature, a deliberately built structure, or something in between, a natural mound that was reshaped and augmented by human hands to serve a purpose we can only partly reconstruct.

A crannog, in early medieval Ireland, was typically an artificial or partially artificial island, built up in a lake and reached by a submerged causeway, and used as a defended dwelling place by people of some local standing. This site shares several of those features without quite conforming to the standard picture. The mound has been scarped around its edges, giving it a more deliberate profile, and a narrow stone causeway, ten metres long and only fifty centimetres wide, runs from roughly its midpoint to the shore in a north-east to south-west orientation. A kidney-shaped platform sits across its upper surface. Scattered around the water's edge nearby are smaller rocky islets and platforms that also appear to have been deliberately modified, the most prominent sitting fifteen metres out from shore to the west-south-west. The site was identified during systematic fieldwork, and no finds have been recovered from its surface. Its suggested early medieval date rests largely on proximity rather than excavated evidence: a ringfort sits ninety metres to the north, and a more conventionally recognised crannog lies just a hundred and fifty metres to the south. That cluster of monument types, each associated with early medieval settlement and territorial organisation, suggests this stretch of Lough Derravaragh's northern shore was a place of some significance, even if the precise function of this particular mound remains open.