The structure is what is known as a univallate rath, meaning a ringfort enclosed by a single bank and ditch rather than the multiple concentric rings found at more elaborate examples. These earthworks were built, typically in the early medieval period, as defended farmsteads or high-status enclosures, and they survive in their thousands across Ireland, though the majority are in varying states of decay and obscurity.

At Ballyduhig, the enclosing bank is around three metres wide and rises between half a metre and one metre above the ground on its outer face, with a somewhat lower internal profile of around 0.3 metres. Outside the bank runs a fosse, the ditch that would originally have made the whole structure considerably more imposing, averaging five metres across and up to one metre deep. The difference in height between the interior and exterior measurements hints at centuries of material creep, slippage, and soil accumulation. C. Toal's North Kerry Archaeological Survey, published in 1995, records this site as extremely overgrown, which suggests that vegetation has done as much as time to soften its original geometry. The fosse and bank remain measurable, but the enclosure as a whole has been largely reclaimed by whatever scrub or field growth surrounds it.