The one at Derryorgan in north Cork does neither. It reveals itself only from the air, and even then only partially, as a cropmark, the faint differential in how grass or grain grows above a buried ditch betraying something substantial lying beneath the surface.

An aerial photograph taken in July 1989 as part of the Cork Archaeological Survey Aerial Photography programme captured an incomplete outline of what appears to be a large, roughly rectangular enclosure. The visible sections include a south-western side running approximately 110 metres, a north-eastern fragment of around 40 metres, and a gently curving arc of some 260 metres along the north-western side, all formed by the cropmark of a fosse, the term used for a ditch dug as part of a defensive or boundary earthwork. The north-western edge abuts an existing field fence, which has likely obscured or overlain part of the original outline. What makes the site more complex, and more interesting, is what sits inside it. A second, circular enclosure occupies the north-western quadrant and briefly shares the fosse of the outer perimeter along one side. There is also a small circular cropmark, roughly ten metres in diameter, near the western corner of the larger enclosure. The relationship between these features, whether they were built together or accumulated over generations, is not clear from the surface evidence alone. Nested enclosures of this kind, where smaller structures are set within a larger boundary, are known from other Irish sites and may reflect extended settlement, agricultural use, or the reuse of an older boundary by later occupants, though none of that can be stated with certainty for Derryorgan specifically.

Because the site survives only as a buried feature with no upstanding remains, there is nothing to see on the ground itself. The enclosure exists, for now, chiefly as an outline in a single photograph, a shape pressed into the soil of a north Cork field and visible only when the light and the season are right.