It is the kind of place that makes you wonder immediately why someone went to the trouble of building anything there at all, and what that building was actually for.

The enclosure measures approximately 21.2 metres north to south and 24.4 metres east to west, making it a modest but deliberate construction. Its defining feature is a low earth and stone bank, roughly 2.5 metres wide at the base and tapering to about a metre at the top, with an interior height of 0.4 metres and an exterior height of 0.6 metres. A narrow entrance, around 2 metres wide, faces to the south-east. The interior is flat, with natural rock outcrop breaking through the surface. Associated field banks extend around the site, and some of these may represent the remains of earlier or related structures, though their precise nature is uncertain. Enclosures of this general type, sometimes called ring enclosures or cashels depending on their construction, were used across early medieval Ireland for a variety of purposes, from livestock management to domestic settlement or even ceremonial use, and their summit locations sometimes reflect a concern with visibility as much as with practicality. The site at Coolnacrutta was identified through a Geological Survey of Ireland aerial photograph, which is often how such low-profile earthworks, barely readable at ground level, first come to the attention of researchers.