The ringfort at Lisheenahevnia, County Galway, belongs firmly to the second category. Marked on the nineteenth-century Ordnance Survey six-inch maps as a roughly circular enclosure of around twenty-five metres in diameter, it sits on a low rise in ordinary grassland, and when archaeologists visited in April 1985 they found almost nothing to see. A slight elevation on the western side was all that remained at ground level.

A ringfort, or rath, is one of the most common monument types in the Irish landscape, typically a circular area enclosed by one or more earthen banks and ditches, used as a farmstead during the early medieval period, roughly the fifth to twelfth centuries. Thousands survive across the country in varying states of preservation. The Lisheenahevnia example represents the less visible end of that spectrum: centuries of agricultural activity on the low, workable ground have flattened whatever bank and ditch once defined the site. What saves it from complete obscurity is aerial photography. Seen from above, crop or soil differences can reveal the ghostly outline of a buried or levelled enclosure that is entirely invisible to someone standing in the field, and that is precisely what happened here, with the site's circular plan still legible in aerial images.