At Knocknacolan in north County Cork, a roughly circular earthwork measuring 33 metres across sits on a west-facing slope in pasture, its interior now occupied by a large elongated mound of dumped rubble running north to south through the centre, and a shed built hard against the inner face of the western bank. The enclosing earthen bank, planted along its crest with coniferous trees, still stands to an external height of 1.5 metres, with an external fosse, essentially a surrounding ditch, reaching a depth of 0.8 metres along the arc from the north-west to the south-south-east.

Ringforts, known in Irish as raths when constructed from earth and bank rather than stone, are among the most common archaeological monument types in Ireland, with estimates suggesting tens of thousands once dotted the countryside. Most date to the early medieval period, roughly the fifth to twelfth centuries, and functioned as enclosed homesteads for farming families of varying social rank. The Knocknacolan example retains two clear breaks in its bank, one to the south-south-east and one to the north-west, measuring 3.4 metres and 3.5 metres wide respectively. The north-west opening is flanked by gate piers, a detail that preserves something of the original sense of a formal, bounded entrance to what would once have been a domestic compound. A second circular enclosure lies approximately 30 metres to the south-east, hinting that the immediate landscape was more densely organised in the early medieval period than the present pastoral setting suggests.