The roughly oval earthwork, measuring approximately 43 metres east to west and 30 metres north to south, is defined not by a standing wall or a clear bank but by an irregular scarp, a low natural-looking edge in the ground that could easily be mistaken for nothing more than a shift in the slope of a field. One road cuts across it from north to south-west, another from south-west to south-east, and together they reduce whatever remains to a fragmented set of arcs.

Enclosures of this general type are scattered across the Irish landscape and are difficult to date without excavation. The name Cahernagarry contains the element "caher", an anglicisation of the Irish "cathair", which typically refers to a stone fort or enclosure, suggesting a local memory of something bounded and deliberate here, even if the physical remains no longer make that obvious. The enclosure sits on a gentle south-facing slope in pastureland, and within the eastern half of the interior there are a number of low banks of earth and stone, the kind of subtle internal features that might indicate subdivision, later reuse, or simply centuries of field management gradually reworking whatever was originally built. Very little of the original structure survives in legible form.