The bank has been absorbed into the working field fence system over the centuries, so what was once a deliberate enclosure has gradually become part of the agricultural furniture of the landscape. That kind of slow assimilation is common enough with ringforts, yet it also makes them easy to miss entirely.

A ringfort, or rath, is a roughly circular enclosure formed by one or more earthen banks and ditches, used primarily as a defended farmstead during the early medieval period in Ireland, roughly between the fifth and twelfth centuries. The example at Rathnacarton is modest but structurally legible. The enclosure measures 42 metres across in both directions, and the earthen bank survives to an internal height of around 1.6 metres and an external height of 1.75 metres along the western to northern arc, where it is accompanied by an external fosse, a defensive ditch, around 0.65 metres deep. Elsewhere the boundary takes the form of a scarp, a steep natural or cut slope, roughly 0.9 metres high, with a slight internal lip. One of the more practical details preserved here is that the interior of the enclosure has been deliberately raised on its eastern side to level it out against the natural fall of the hillside, the whole thing sitting on an east-facing slope and currently in tillage. That kind of earthmoving, calculated to create a usable level platform, speaks to the care with which whoever built this place thought about everyday life inside it.