A circular enclosure roughly 58 metres across lies beneath the farmland at Ladycastle in County Kildare, invisible from the ground and only legible from the air. It appears in a Digital Globe aerial photograph as a cropmark, the kind of ghostly outline that forms when buried earthworks cause crops above them to grow at slightly different rates, revealing shapes that centuries of ploughing have otherwise erased. What survives here is the trace of a fosse, a defensive or boundary ditch, that once defined a curvilinear enclosure of the sort associated broadly with early medieval settlement in Ireland, though no precise date has been confirmed for this particular site.

About 110 metres to the south-south-east, the same aerial imagery picks up further cropmarks, these ones linear rather than curved, suggesting the remains of old field boundaries. Their relationship to the enclosure is uncertain. Some of these linear features do appear on the Ordnance Survey six-inch map published in 1838, which raises the possibility that at least part of what is visible from the air belongs to a field system no older than the eighteenth or early nineteenth century, a period of significant agricultural reorganisation across the Irish countryside. Whether any of these boundaries predate that era, and whether they connect in any meaningful way to whoever once lived within the enclosure, remains an open question.