The one at Colvinstown survives as a circular, steep-sided earthen platform roughly 17 metres across and rising to a maximum height of 2.5 metres, enclosed by a bank and an external fosse. A fosse, in this context, is simply a ditch dug around the outside of the enclosure, its presence here indicated by a persistently waterlogged area rather than by any obvious cut in the ground. The overall structure, bank and all, extends to about 32 metres in diameter.

Ringforts, known in Irish as raths when built from earth rather than stone, were the standard settlement form of early medieval Ireland, typically dating from somewhere between the sixth and tenth centuries, though many were in use earlier or later. They functioned primarily as farmsteads, the bank and fosse providing a boundary as much social as defensive, enclosing a household and its livestock against both animals and neighbours. What makes the Colvinstown example quietly puzzling is the absence of any visible entrance or surviving trace of internal features. The platform is well-preserved and geometrically regular, yet it gives nothing away about how people moved in and out, or what stood inside. Its neighbour to the west-northwest, another ringfort on the same general slope, raises the further question of whether these two enclosures were in use at the same time, by related households, or at different periods entirely.