This ruined tower house, now reduced to just its ground and first floors, occupies the northeast corner of an irregularly shaped elevated area measuring roughly 43 metres north to south and 81 metres northeast to southwest. The castle itself is relatively modest in size, measuring 9.8 metres by 7.2 metres externally with walls approximately 1.5 metres thick. A long narrow ridge extends 35 metres from the castle’s western wall, whilst at least six depressions, four of them incomplete, can be found around the edges of the raised ground.

The castle’s main entrance appears to have been located on the first floor of the western wall, accessed by steps in the northwest corner that begin two metres above ground level; a design suggesting the ground floor served primarily as storage space. Despite its ruined state, several architectural features remain visible, including a segmental pointed arch over the staircase doorway and remnants of a garderobe on the western wall. At the base of the rise to the northwest stands a rectangular stone structure measuring 7.6 by 12.5 metres externally, with substantial walls 1.6 metres thick and a two metre wide opening on its southern side. Beyond this lies another depression, roughly 5 by 8 metres and 0.8 metres deep, both features possibly serving defensive functions connected to the castle.

Historical records about Rahoneen Castle remain frustratingly sparse. Writing in 1756, Smith noted it was formerly a residence of the Bishop of Ardfert, whilst John O’Donovan’s 1841 account claims the castle was destroyed by Cromwell’s forces. These tantalising fragments hint at a site that witnessed both ecclesiastical power and military conflict, though much of its story remains lost to time.