A rath, to use the Irish term, is a roughly circular earthen enclosure, typically dating from the early medieval period and used as a farmstead, its bank and ditch marking the boundary of a family's domestic world. At Coolroe, that bank has been reduced to intermittent, poorly preserved sections, its internal height little more than 0.4 metres and its external face only marginally taller. The enclosure measures approximately 32 metres east to west and 30 metres north to south across a level interior, the centre of which holds a small, roughly circular marshy area about 5 metres in diameter, a soggy hollow that hints at some disturbance or structural feature beneath.

The site has been losing ground for a long time. A field boundary running roughly south-southeast to north-northwest has cut across the western side, and a nearly linear scarp truncates the enclosure to the south, leaving the original circuit incomplete. When the Ordnance Survey recorded this landscape in 1846, its 6-inch map showed a circular enclosure of around 40 metres in diameter, already clipped on its western edge by a lane. That earlier measurement suggests the earthworks were more legible in the nineteenth century than they are now, and the shrinkage between the two records is a quiet measure of how thoroughly agricultural activity can erode ancient boundaries. The site sits on a break of a south-facing slope and is set within pasture, which at least means it has not been ploughed out entirely. Considerably more intriguing is the associated souterrain, a type of underground stone-lined passage or chamber frequently found in conjunction with raths across Ireland, likely used for storage or concealment, recorded separately and linked to this enclosure in the archaeological record.