The site at Cornacarrow is classified as a fort, a broad term used in Irish archaeology to describe enclosed settlements of the early medieval period, though the precise date and function of any individual example can be difficult to pin down without excavation. What makes this one quietly arresting is the tension between its survival and its compromise: the form is still there, but the landscape has been working against it.

The enclosure sits on a northwest-to-southeast spur, oriented to take advantage of the elevated ground. It measures roughly 52 metres on its longer axis and 47 metres across, and the interior is noticeably domed, rising to about two metres at the northeast end and four metres at the southwest. The boundary is defined by a scarp rather than a built wall or an earthen bank with a fosse, that is, a ditch cut around the outside, and no entrance is currently visible. Two field banks have encroached on the structure at some point, one truncating the perimeter at the northwest and another cutting directly across the interior. These divisions suggest the enclosed area was absorbed into the surrounding farmland at some stage, its original unity overwritten by later field management. The domed profile and overall dimensions are consistent with a ringfort, one of the most common monument types in the Irish countryside, though the absence of an obvious fosse is worth noting.