The site at Coolrus is a rath, the Irish term for a ringfort, which was the most common form of early medieval settlement in Ireland. These enclosures, typically dating from roughly the sixth to the twelfth centuries, served as farmsteads for a single family or small community, their raised banks and ditches providing a degree of protection for people and livestock alike. What makes the Coolrus example quietly arresting is precisely how thoroughly it has been absorbed back into the landscape it once commanded.

The earthwork takes the form of a circular area approximately twenty metres in diameter, defined by a scarped, or artificially cut and sloped, inner edge. That scarp stands around 0.65 metres high and extends roughly 1.1 metres in width, with an external fosse, essentially a shallow ditch, running around the outside. The fosse survives to a depth of about 0.2 metres and a width of 1.5 metres, dimensions that suggest it was never a particularly formidable defensive feature, though even a modest ditch and bank combination would have made a meaningful barrier in an agrarian landscape. The northeast side of the scarp has been partially levelled, likely the result of agricultural activity over the centuries. The site was recorded and compiled by Denis Power, with notes uploaded in August 2011.

Accessing the site requires crossing private farmland, so permission from the landowner is the sensible first step. Once there, the dense overgrowth that smothers the interior makes it difficult to read the earthwork clearly from the inside; the perimeter is easier to trace by walking the outer edge and watching for the slight rise and fall of the ground underfoot. The external fosse in particular rewards slow, careful observation rather than a quick glance. Visiting in late winter or early spring, before the growing season takes full hold, would give the best chance of seeing the scarp's profile without fighting through vegetation.