A cropmark roughly 36 metres in diameter appeared in a Google Earth image captured in August 2021, its outline traced not by stone or earthwork but by the differential growth of crops above buried features. Where subsurface walls, ditches, or banks alter the moisture and nutrients available to roots, the vegetation above responds accordingly, growing taller or shorter, greener or paler, and in doing so quietly outlines whatever lies beneath.

Cropmarks of this circular type are frequently associated with early medieval enclosures, the kind that once surrounded a farmstead, a ringfort, or occasionally an ecclesiastical site. Ringforts, known in Irish as ráth or lios depending on their construction, were the dominant settlement form in Ireland from roughly the early centuries of the first millennium through to the Norman period, and many thousands are known across the country. Some survive as earthworks; others, like this one at Shanonagh, have been levelled by centuries of cultivation and survive only as ghost impressions in the soil. The Westmeath landscape is dotted with such sites, many of them still unexcavated and known only through aerial observation. This particular site was identified by Jean-Charles Caillère and compiled by Caimin O'Brien in late 2021, a reminder that systematic scrutiny of satellite imagery continues to expand the inventory of known archaeological sites in Ireland.