It measures roughly 2.75 metres north to south and 2.5 metres east to west, and its interior rises in a low, domed profile. What defines it is a shallow surrounding fosse, a type of ditch cut into the earth, just 13 centimetres deep and 1.25 metres wide. That combination, a domed interior ringed by a fosse, is what places it in the category of ditch-barrow, a form of prehistoric funerary monument in which the defining feature is not a high mound but a encircling earthen cut, modest almost to the point of invisibility.

What makes the Rathcoun example quietly remarkable is not any one feature in isolation but its context within the surrounding ground. The barrow sits on the exterior of a nearby enclosure, and within a short radius there are at least three related monuments: two further ditch-barrows lying 5.5 metres and 20 metres to the east respectively, and a small possible mound barrow approximately 14 metres to the south-south-west. Taken together, the cluster suggests this part of Tipperary once functioned as a focus for burial or ceremonial activity, the individual features modest enough to have survived centuries of agricultural improvement without drawing much attention, yet numerous enough to indicate this was no isolated or incidental choice of ground.