Measuring roughly 29 metres across, it presents as a slightly raised platform defined by a scarp, a partial inner fosse, and a low outer bank, with what appears to be a causewayed entrance gap at the south-east. A ringfort, in the Irish tradition, was typically a farmstead enclosed by one or more earthen banks, used broadly from the early medieval period onward. A ring-barrow, by contrast, is a funerary monument, a burial mound surrounded by a circular ditch or bank. The Castleleiny site was once categorised as the latter and has since been reclassified as the former, a small but meaningful distinction that says something about how cautiously the archaeology of this landscape is still being read.

What makes the site particularly interesting is the relationship between human construction and natural topography. Rather than raising the interior from flat ground, whoever built this enclosure worked with a pre-existing low hillock, scarping its sides and enclosing it at the base so that the interior sits naturally elevated above the surrounding terrain. The outer bank, just 0.8 metres high externally and around three metres wide, is modest by any measure, but combined with the scarp and the natural rise of the ground, the effect would have created a clearly defined and defensible, or at least conspicuous, space. There is also evidence of quarrying on the eastern side, suggesting the site was not simply occupied but actively worked in some capacity. The surrounding countryside is undulating and open, and the ridge position would have offered extensive views in both directions along its east-west axis, which may well have been the point.