This is a rath, a type of ringfort formed by a raised earthen bank enclosing a roughly circular area, which would once have enclosed a farmstead or small settlement in early medieval Ireland. The bank here described a subcircular shape measuring around 31 metres north to south and 28.6 metres from west-southwest to east-northeast, but from the west-southwest around to the north, no surface trace of it survives at all.

Raths of this kind were built in their thousands across Ireland, mostly during the first millennium AD, and served as the basic unit of rural life for farming families of modest means. They were not fortifications in any military sense, despite the name sometimes attached to them; the enclosing bank offered security for livestock and a degree of social demarcation as much as physical defence. The Kilgevrin example is now poorly preserved even by the modest standards of surviving earthworks, reduced by centuries of agriculture and the slow work of erosion along a river valley. A separate enclosure sits roughly 80 metres to the southeast, suggesting that whatever activity once concentrated here was not entirely isolated, though the relationship between the two features remains unresolved.