A cashel is a stone-walled enclosure, typically of early medieval date, and this one, known as Cahernanackree or Cathair na nAcraí, is of bivallate construction, meaning it once had two concentric enclosing walls. What survives is heavily ruined, but somewhere within the rubble, a roof of five stone slabs still covers a small souterrain chamber measuring roughly 2.2 metres by 1.5 metres and only 0.7 metres high. A souterrain is an artificially constructed underground passage or chamber, usually built from drystone walling, and associated in Ireland with early settlement sites where they may have served for storage, refuge, or both. The only way into this particular chamber now is through an accidental opening in the collapsed stonework, not through any original entrance.

When a University College Cork team visited the site in 1940, considerably more was visible. The original entrance and further chambers and passages could still be accessed, and the interior of the cashel held a cluster of structures: a circular hut approximately 1.8 metres in diameter abutted by a triangular hut and two rectangular huts, along with a series of about seven circular depressions of similar diameter running along the south-western edge of the enclosure. None of these features are now discernible above ground. Among the objects found in the chambers was what appeared to be a stone mining hammer, an unusual find that raises quiet questions about what activity was taking place here. J. Cuppage documented the site in the 1986 Dingle Peninsula archaeological survey, and the cashel sits directly opposite Minard Castle across the beach, a spatial relationship that places it within a landscape that was clearly in use across very different periods.