It was simply not on the map, which raises a quiet question about how thoroughly early surveyors read the landscape, and how easily an earthwork can become invisible when it has been absorbed into the working fabric of a farm.

A ringfort, or rath, is a roughly circular or oval enclosure defined by one or more earthen banks and ditches, built primarily during the early medieval period in Ireland, roughly between the fifth and twelfth centuries, as a defended farmstead or high-status residence. The Corkagh Beg example sits on an east-north-east-facing slope in hilly coastal pasture and is subrectangular rather than truly circular, measuring approximately 20.7 metres along its north-north-west to south-south-east axis and 19.5 metres across. The enclosure is defined by a scarp, essentially a sharp drop in the ground surface, which varies in height from around half a metre on the east side to 1.25 metres on the south-south-west. Along the western arc, a fosse, the ditch that would originally have accompanied the bank, remains well defined, running about 4.3 metres wide and 0.3 metres deep. A survey carried out by the Office of Public Works in 1991 noted a low earth and stone bank along the upper edge of the scarp at the south-east, but that feature has since disappeared entirely from the visible surface. The western and north-western stretch of the perimeter has been quietly consumed by a field boundary running north-north-east to south-south-west, the kind of incremental annexation that erodes earthworks over generations without any single act of demolition. No original entrance can now be identified.