A ringfort, or rath, is an enclosed farmstead of the early medieval period, typically defended by one or more earthen banks and ditches. This particular example is unusual in that it shows no visible trace of an external fosse, the ditch that normally runs just outside such a bank, and its original entrance has been lost entirely. What survives is a low, steep-sided bank of earth and stone, reduced in places to a mere scarp along its southern and western arc, while the interior rises gently from the perimeter up to a central high point, giving the whole structure a subtle domed quality from within.

The site sits on a low round-topped hillock within what was once the deer park of Killynan House, a setting that partly explains its survival: ornamental parkland and managed demesne ground often insulated ancient monuments from the ploughing that erased so many similar earthworks elsewhere. The Ordnance Survey's six-inch map of 1837 already recorded it as an oval earthwork, suggesting it was a legible feature in the landscape at that date. By 1972, when it was formally described, a small hut site was noted on the upper edge of the scarp at the north-east, a detail that had been visible two years earlier on an oblique aerial photograph taken in July 1970. This small concentration of monuments is denser than the lone ringfort might suggest: a second ringfort lies roughly 40 metres to the east, an enclosure approximately 150 metres to the north-west, and a further hut site around 175 metres in the same direction. An old field bank, probably of much later date, cuts across the scarp at the south-south-west and west, a reminder that later agricultural boundaries were often imposed across far older earthworks without ceremony.