A ring-ditch, in archaeological terms, is the buried or near-buried remnant of a circular ditch, the fosse, that once enclosed a structure of some kind, whether a dwelling, a ceremonial space, or a funerary monument. What survives at Creggannacourty is a cropmark, the faint differential growth of crops or grass over buried features below the soil, which outlined a roughly circular enclosure approximately twenty metres in diameter when captured in an aerial photograph taken in July 1989.

The photograph was taken as part of a systematic aerial survey, and the image it preserved is genuinely faint. The ring-ditch sits within a wider landscape that appears, from above, to carry further traces of human organisation. Linear cropmarks nearby have been interpreted as possible relict field boundaries, the ghost-lines of an agricultural system that may stretch back centuries or further. Roughly a hundred metres to the east, a separate subrectangular enclosure has also been recorded, suggesting that this particular corner of north Cork was, at some point, a place of some activity rather than a single isolated feature in an otherwise empty landscape.