A circular enclosure announces itself only as a cropmark, the kind of trace that appears when buried features affect how plants grow above them. Ditches, banks, or filled pits alter the soil's moisture and nutrient levels, causing the crops overhead to ripen at different rates or grow to different heights, and from altitude the pattern becomes unmistakeable.

The Gormanstown enclosure was recorded in a single aerial photograph taken on 16 July 2006 by Michael Moore. Circular enclosures of this type are relatively common across Ireland, though individually most remain undated without excavation. They could represent the remains of a ringfort, a class of enclosed farmstead built primarily between the seventh and tenth centuries, or something considerably older, a Bronze Age or Iron Age settlement boundary, a ritual enclosure, or a burial site. The tillage field it occupies is, in a sense, the reason it survives in any recorded form at all; arable crops are uniquely sensitive to subsurface variation in a way that pasture simply is not, which means ploughed ground occasionally reveals what grassland conceals for centuries.