Roughly circular and measuring just under 43 metres north to south and just under 40 metres east to west, it sits on level ground above a south-facing slope, the kind of position that would have offered both good drainage and a commanding view of the surrounding landscape. An earthen bank encloses the interior, and an external fosse, a defensive ditch, runs around the outside from the north-east to the south-south-west. A gap of about four metres in the bank to the north-east marks what was likely the original entrance.

Ringforts of this type, known in Irish as raths, were the most common form of rural settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. They served as enclosed farmsteads rather than military fortifications, the bank and ditch providing security for livestock and a household rather than a garrison. What makes Clonfadda particularly interesting is the presence of a souterrain in the interior. A souterrain is an underground stone-lined passage or chamber, usually associated with storage, refuge, or both, and their appearance within ringforts is well documented across Munster and beyond. The fosse on the north-western to northern side has been partly incorporated into a stone field boundary, with stones cleared from the ploughed field dumped at its base, the working rhythms of later agriculture pressing up against something far older without quite erasing it.