A cropmark, the faint differential in how crops ripen above buried ditches and disturbed soil, betrays the presence of a semicircular enclosure roughly 38 metres across, its entrance oriented to the south-east. The western arc of the enclosure does not need a ditch to define it; the natural break of slope on the hillock's edge does that work instead, suggesting that whoever laid out this site was reading the landscape carefully and building with it rather than against it.

An aerial photograph taken on 29 July 1996 captured the cropmark in sufficient detail to reveal more than a simple enclosure. An outer fosse, a ditch dug for defence or drainage, runs concentrically around the north-eastern quadrant before curving eastward, where it appears to connect with a broader curvilinear field system extending up to around 80 metres to the north-east, east, and south-east. This suggests the enclosure was not a solitary feature but part of a planned agricultural or settlement landscape, the boundaries of fields and habitation areas laid out in relation to one another. A second concentric enclosure sits approximately 90 metres to the north, also positioned to overlook the break of slope, raising the possibility that this part of Dunmore once held a cluster of related enclosures, each making use of the same elevated, well-drained ground.