It was recorded on the Ordnance Survey map of 1838, which means cartographers once considered it visible and worth marking, but at some point between that survey and the present the feature was levelled entirely. There are no surface traces left to speak of.

Circular enclosures of this kind are among the most common archaeological features in the Irish landscape. They are typically the remains of a rath or ringfort, an enclosed farmstead of the early medieval period, roughly the fifth to twelfth centuries, defined by one or more earthen banks and ditches thrown up around a dwelling or small settlement. The Coollisduff example was noted as part of a local survey covering the Ballinrobe district, including the areas around Lough Mask and Lough Carra, compiled by D. Lavelle in 1994. That survey drew on the earlier OS mapping as its evidence, which tells us the enclosure was already being treated as a historical curiosity rather than a functioning landscape feature by the Victorian era. Its disappearance since then, through agricultural levelling, is a fate shared by a considerable number of similar sites across Connacht.