This one exists almost entirely as a rumour in the soil. At Boherascrub in north County Cork, a circular enclosure of roughly forty metres in diameter shows up not as any visible earthwork but as a cropmark, the kind of ghostly outline that only emerges in aerial photographs when drought or differential soil moisture causes crops above buried features to grow at a slightly different rate than their neighbours. The enclosure is detectable precisely because it is invisible at ground level.

The site came to light through an aerial photograph, reference R528 in the Geological Survey of Ireland Air Photography collection, which caught the faint trace of a bank curving along the northern side of a field fence. That fence itself offers a subtle clue: it curves slightly in the area of the site, suggesting the field boundary may have been laid out in deference to something already present in the landscape, or that it follows the ghost of an older boundary. Circular enclosures of this kind are common across Ireland and typically date from the early medieval period, roughly the fifth to the twelfth centuries, though without excavation it is impossible to assign a confident date to any individual example. They are sometimes ringforts, the enclosed farmsteads of prosperous farming families, and sometimes the remains of earlier Bronze Age settlements. The forty-metre diameter here falls within the range typical of smaller ringforts, though the classification remains tentative.

There is little to see at Boherascrub without the aerial photograph to guide interpretation. The field fence curves, the ground does not obviously yield anything, and the enclosure remains hypothetical until further investigation confirms its nature. It is the kind of site that rewards knowing it exists more than visiting it.