Near Lowtown in County Kildare, a circular feature roughly thirty metres across lies buried beneath farmland, invisible at ground level and detectable only from the air, and even then only under the right conditions. It belongs to a category of site known as a cropmark enclosure, where the buried remains of an ancient ditch or bank cause the vegetation above to grow differently from the surrounding soil. In a dry summer, crops rooted above a filled-in ditch draw on residual moisture and grow taller or greener, while those above compacted material may be stunted. The result, for a few weeks each year, is a ghostly outline pressed into the landscape like a watermark.

This particular enclosure came to light through aerial photography taken on 28 June 2018, when a Digital Globe satellite image captured the cropmark in sufficient clarity to record it. The information was supplied by Anthony Murphy, a researcher with a long interest in aerial and remote sensing evidence for prehistoric and early medieval sites across Ireland. The enclosure is roughly circular in plan, approximately thirty metres in diameter, a scale consistent with a wide range of site types in the Irish archaeological record, from ringforts used as enclosed farmsteads in the early medieval period to earlier Bronze Age or Iron Age ceremonial enclosures. Without excavation, the precise date and function remain open questions.