The 1838 six-inch OS map shows it clearly: a circular embanked enclosure roughly 35 metres across, sitting on the northern end of a drumlin in Rockfield, County Mayo, with a feature marked simply as "Cave" in its north-east quadrant. By the time later editions were published, the rath had been omitted entirely, its cartographic existence erased even as the earthwork itself continued to weather in the pasture above.

What remains on the ground is a roughly circular raised platform, measuring about 34 metres north-north-east to south-south-west, with a broadly sloping scarp that still reaches 1.5 metres in height on the northern side and 2 metres on the west. A short section at the south has been levelled flat, the result of past agricultural activity that also reduced the enclosing bank in places. The "Cave" noted on that 1838 map survives as a souterrain, an underground stone-lined passage of the kind commonly built within Irish ringforts, likely for storage or refuge. It lies in the south-east quadrant, sheltered now beneath a small copse of hazel and hawthorn rather than the north-east position the old map suggested, a discrepancy that hints at how casually such features were recorded by early surveyors working across unfamiliar terrain. A rath of this type, a ringfort defined by an earthen bank and interior space rather than stone walling, would typically date to the early medieval period, roughly the sixth to tenth centuries, when such enclosed farmsteads were the standard unit of rural settlement across Ireland.