It is a rath, the Irish term for a ringfort, the type of enclosed farmstead that was the dominant form of rural settlement in early medieval Ireland, built and occupied roughly between the fifth and twelfth centuries. Thousands survive across the country in varying states of preservation, and this one near Johnswell is modest by any measure, but its quiet persistence in the landscape is its own kind of interest.

The enclosure is oval in plan, measuring approximately 35 metres north to south and 40 metres east to west. It is defined by a bank, around 5.5 metres wide overall, with an outer fosse, essentially a drainage or defensive ditch, running alongside it. The bank still stands to an external height of between 1.15 and 1.7 metres in places, which is a reasonable survival given the centuries of agricultural activity that have reduced or erased so many comparable sites. There are three gaps in the bank, to the north, north-east, and west; the northern one appears to be a modern break, while the other two may represent original or early entrances, though the overgrown interior made close inspection difficult at the time of survey. The site sits on a slight ridge aligned north-west to south-east, a positioning that would have offered the original occupants a view across the south-west-facing slope below, the kind of subtle topographical advantage that early farmers consistently sought out when choosing where to build.