The outline of the building, roughly 13 metres east to west and just under 6 metres north to south, is still legible if you know what you are looking for. A gap of about 1.7 metres survives in the southern wall, slightly west of centre, which would once have served as the entrance. Nothing rises to much more than a metre in height now, yet the footprint is clear enough.

What makes Kilcashel quietly remarkable is not the church itself but the landscape that contains it. The building sits at the centre of a large, roughly oval enclosure, approximately 140 metres on its longer axis and 100 metres on its shorter, defined by a substantial earthen bank some 3.4 metres wide. This kind of enclosure, sometimes called a cashel when built in stone or simply an early ecclesiastical enclosure when formed in earth and bank, is a common feature of early Irish Christian sites, where the boundary marked sacred ground as much as it offered practical protection. At Kilcashel the enclosure bank survives well on most sides, though a straight section of modern field wall has replaced the original boundary at the north-east, where the early bank would probably have curved away northwards. Intriguingly, there are no grave-markers visible anywhere within the enclosure, which is unusual for a site of this type and leaves the question of how the space was used somewhat open. A second possible enclosure lies immediately to the east, suggesting the site may have been more extensive or more complex in its arrangement than what survives today.