At Ballynaboul in north Cork, a roughly circular enclosure measuring about 29.5 metres east to west and 28.8 metres north to south sits on a gentle north-facing slope, its raised bank still standing around 1.1 metres high both inside and out. This is a rath, the Irish term for a ringfort, the most common monument type in the Irish countryside. Ringforts were typically enclosed farmsteads of the early medieval period, roughly the fifth to twelfth centuries, where a family and their animals lived within a defended or demarcated boundary. The earthen bank here is the defining feature of that enclosure, and it has endured well.

Surrounding the bank on its south-south-west to west-south-west arc is an external fosse, a ditch dug to provide the material for raising the bank and to add a further obstacle to anything approaching from outside. The fosse survives to a depth of about 0.6 metres on that side, while fainter, silted-up traces of it can still be read to the east and south, suggesting it once ran further around the circuit. Two breaks interrupt the bank: a relatively narrow gap of about 1.45 metres to the east, which may represent an original entrance, and a second gap worn through to the south-east, more likely the result of long agricultural use than any deliberate design. The trees planted across the bank and its interior are common to many Irish ringforts; farmers frequently left these earthworks untouched, whether from practical difficulty or a lingering unease about disturbing such places, and the resulting tree cover now makes them visible from a distance in otherwise open land.