The example at Portnashangan, Co. Westmeath, does almost the opposite. It has been so thoroughly flattened over time that today it survives largely as a ghost, readable less by eye on the ground than from the air, where it shows up as a crop mark, a faint but legible difference in vegetation growth that betrays the buried archaeology beneath.

A ringfort is a roughly circular or oval enclosed settlement, typically from the early medieval period, bounded by one or more earthen banks and ditches. This particular example sits on a south-south-east facing slope of a low rise in poor grassland, positioned to look out over Lough Owel, which lies roughly 250 metres to the south-west. When the Ordnance Survey drew up its Fair Plan map in 1837, the earthwork was still distinct enough to be recorded as a broad oval shape and annotated simply as "fort". The structure was originally substantial; the enclosed area measures approximately 45 metres north to south and 40 metres east to west, with an external fosse, meaning a shallow ditch running around the outside of the bank. By the time modern survey work was carried out, the bank had become so degraded that it was only traceable along the northern to south-eastern arc, with the rest effectively gone. A Digital Globe aerial photograph from November 2011 confirmed what ground-level inspection could barely suggest, the crop mark remaining as the most legible trace of what was once a significant enclosed site.