It is in fact a rath, the Irish term for a ringfort, an enclosed circular settlement of the early medieval period, typically built between roughly 500 and 1000 AD. This one at Ballyandreen on the Dingle Peninsula is modest in scale, with an internal diameter of eighteen metres, and its enclosing bank rises no more than 1.25 metres on the outer face, averaging closer to half a metre on the interior side. The entrance gap on the south-east has been widened considerably over the centuries, to around six metres, likely to accommodate agricultural traffic that had no particular reverence for what it was passing through.

Raths of this kind were once interpreted almost universally as defensive structures, but current thinking tends to see them as enclosed farmsteads, the earthen bank and whatever timber palisade once sat atop it serving to define a household's space and keep livestock secure rather than to repel serious attack. Thousands survive across Ireland in varying states of preservation. The Ballyandreen example is described as univallate, meaning it has a single enclosing bank rather than the two or three concentric rings found at more elaborate sites. It occupies fairly level ground at the lowest and most westerly point of the ridge extending westward from Flemingstown mountain, a position that would have offered some shelter without sacrificing access to the surrounding land. The interior is largely featureless today, save for a large pile of field clearance stones heaped in the north-east quadrant, the accumulated debris of generations of farmers lifting rocks to make cultivation easier elsewhere. J. Cuppage documented the site in the 1986 Corca Dhuibhne archaeological survey of the Dingle Peninsula, a systematic record of the area's extraordinary density of ancient monuments.