Others exist only as shadows in the soil, legible from the air but invisible at ground level. The rath at Garrylough in County Wexford belongs to the second category: a circular enclosure roughly 35 metres across, outlined not by any surviving bank or ditch but by the differential growth of crops above a buried fosse, the term for the wide ditch, here approximately 3 metres across, that once defined the settlement's boundary.

Raths, sometimes called ringforts, were the most common form of rural enclosure in early medieval Ireland, typically serving as defended farmsteads for a single family and their livestock. Most were constructed between roughly the sixth and tenth centuries, though many continued in use beyond that period. What makes the Garrylough example quietly notable is how entirely it has retreated into the landscape. On the level ground of County Wexford, with no obvious topographical drama to preserve it, the fosse has silted and settled until the enclosure is undetectable at the surface. It reappeared only when aerial photographs taken in 2004 caught the cropmark, the slight but telling difference in how plants grow over buried features, tracing its full circular outline. A later series of aerial images from 2012 confirmed the same shape in the same field.