Sitting in level pasture, this ringfort carries a later stone field fence laid directly on top of its inner bank, so that a working boundary of relatively recent farmland has been built over, and in doing so has partly preserved, the earthwork beneath it. That kind of accidental conservation is common in the Irish countryside, but it does not make it any less odd to stand beside a modern field division and realise you are also looking at an early medieval enclosure.

The site is a rath, the most widespread type of ringfort in Ireland, typically constructed during the early medieval period as a defended farmstead for a single family or small kin group. A rath generally consists of a circular area enclosed by one or more earthen banks, often with a fosse, or ditch, running between them. At Carrowkeel, the enclosure measures roughly 40 metres north to south and 41 metres east to west. There are two concentric earthen banks with an intervening fosse, and the inner bank still stands to 1.8 metres in height, retaining traces of its original stone facing. The outer bank and fosse have been largely levelled along the north-west to south-east arc, worn down to around 0.2 metres and 0.3 metres depth respectively. The interior is further complicated by a stone wall running north-west to south-east, bisecting the enclosed space, and in the north-west corner there is a possible souterrain, an underground stone-lined passage or chamber that would have served for storage or refuge. The eastern side of the interior has been left to grow heavily over, obscuring whatever detail may remain there. The survey from which this description derives was compiled by D. Lavelle for a 1994 archaeological survey of Ballinrobe and district, covering the Lough Mask and Lough Carra area.