What survives is not a wall, a mound, or even a hollow in the earth, but a shadow. In aerial photographs taken in July 1989, the buried ditch, or fosse, of a roughly oval enclosure shows up as a cropmark, a phenomenon where variations in soil moisture and depth cause overlying crops or grass to grow differently above buried features, producing outlines legible only from the air. The enclosure measures approximately 80 metres north to south and 40 metres east to west, a substantial footprint for a site that has otherwise left no trace on the surface.

The form suggests a ringfort, the type of enclosed farmstead that was built in Ireland predominantly during the early medieval period, roughly between the fifth and twelfth centuries. Ringforts are among the most common archaeological monuments in the Irish landscape, and yet the one at Knockbarry appears to have been levelled entirely, its banks and ditches ploughed or cleared away until only the disturbed subsoil remained. A second, related site sits approximately 200 metres to the south, also a levelled ringfort, suggesting this part of north Cork was once a small cluster of early settlement activity. Both have since been reduced to traces detectable only through the technology of aerial survey.