The situation is quietly extraordinary: a modern educational building sitting inside the remains of an earthwork that predates it by well over a thousand years, the two existing side by side with very little ceremony about the arrangement.

The rath at Killosolan sits on a hill summit in grassland, looking out over bogland to the northwest. A rath is a roughly circular earthen enclosure, typically associated with early medieval settlement in Ireland, defined by a raised bank and, in many cases, an external ditch or fosse. Here, the fosse is best preserved along the southeastern, southern, and western arcs of the structure, which measures approximately fifty metres across on its east-west axis. The northern and eastern sides have been cut through by roads, leaving the monument in a somewhat fragmentary state overall. Beneath or adjacent to the school building lies a souterrain, an underground stone-lined passage or chamber of the kind often associated with ringforts, likely used for storage or as a place of refuge. The combination of scarp, fosse, and souterrain suggests this was once a reasonably substantial enclosed settlement, even if its above-ground traces are now poorly preserved.