In a field at Waterstown in County Kildare, something circular lies buried just below the surface, invisible to anyone walking past but legible from above. Aerial photography captured in June 2018 revealed a cropmark, the faint but telling discolouration that appears in growing crops when buried features below ground affect how plants take up moisture and nutrients, outlining a roughly circular area approximately twelve metres in diameter. The shape is defined by a fosse, a shallow ditch cut into the earth, and there appears to be a pit at or near the centre.

This kind of feature is generally identified as a ring-ditch, the trace of a monument whose original form and purpose can be difficult to pin down without excavation. Ring-ditches of this type are frequently associated with prehistoric funerary activity, the filled-in remains of a round barrow or burial mound whose earthen body has long since been ploughed flat, leaving only the encircling ditch as evidence. The Kildare lowlands contain a number of such sites, many known only through aerial survey. A second possible ring-ditch has been recorded immediately to the south, suggesting this may be part of a wider, if now largely erased, prehistoric landscape at Waterstown.