The site at Coolrus is a rath, the Irish term for a ringfort, which was the most common form of rural settlement in early medieval Ireland, typically used as an enclosed farmstead by a single family and their livestock. What makes this particular example worth pausing over is its double-bank construction, a feature that sets it apart from the more common single-bank variety and hints at a household of some local standing.

The fort is roughly circular, measuring 43.5 metres north to south and 43 metres east to west. Two earthen banks enclose the interior, separated by a fosse, which is the ditch dug to provide the material for the banks themselves, here about 1.4 metres wide. The inner bank stands up to 1.15 metres on its exterior face, and the outer bank reaches 1.35 metres. Both have been partially levelled along their southern and south-western arc, likely through centuries of agricultural activity, and a break roughly 3.5 metres wide at the south-south-east almost certainly marks the original entrance. The record was compiled by Denis Power and uploaded to the survey database in August 2011, though no excavation appears to have been carried out at the site.

The interior, still under pasture, slopes gently southward. Two features are worth looking for once inside. In the north-east quadrant there is a slightly raised, roughly D-shaped area with indistinct edges, the kind of subtle humping in the ground that can indicate the ghost of a structure beneath the turf. In the south-east quadrant, a large irregular rock outcrop breaks through the surface, a natural feature that the original inhabitants would have simply built around. The site sits in working farmland, so access depends on the goodwill of the landowner, and the earthworks are best read in low winter light, when long shadows throw the surviving banks into relief.