Aerial photography taken sometime between 1973 and 1977 captured earthworks whose pattern suggested the outline of occupation, perhaps walls, enclosures, or levelled structures reduced by centuries of farming to shallow marks in the soil.

The earthworks may be connected to a castle recorded in the townland on the Down Survey, the ambitious mid-seventeenth-century mapping project commissioned by the Cromwellian administration to document land across Ireland, principally for the purposes of redistribution. That castle has never been precisely located on the ground, and the Corstown earthworks offered one of the few potential clues to where it might have stood. By the time satellite imagery was examined in July 2020, agricultural reclamation had smoothed the field enough to obscure most of what the earlier photographs had shown. One feature survives, at least in outline: a fosse, a defensive or boundary ditch, that appears to mark the south-western angle of what might once have been the settlement's edge. It is a thin thread connecting the modern landscape to something that remains, formally, unlocated.