Others survive only as a mark on an old map, a circle drawn in ink over a field that has long since swallowed whatever it once contained. The enclosure at Kilgilky in County Cork belongs firmly to the second category. Roughly twelve metres in diameter, it was recorded on the Ordnance Survey six-inch map of 1842 as a small circular enclosure, indicated by hachures, the short radiating lines surveyors used to suggest a raised or banked edge. Today, in a gently undulating boggy field, there is nothing to see at all.

Circular enclosures of this kind are scattered throughout the Irish landscape and date, in most cases, to the early medieval period, roughly the fifth to the twelfth centuries. At their simplest they consisted of an earthen bank and ditch enclosing a homestead or farmstead, and they are closely related to the ringfort, known in Irish as a ráth or lios. At around twelve metres across, the Kilgilky example would have been on the smaller end of the scale, suggesting a modest agricultural or domestic function rather than a high-status settlement. Whether it was levelled deliberately, perhaps to reclaim ground for farming, or simply eroded away into the surrounding boggy soil over the centuries, cannot now be said. What can be said is that by the time anyone thought to look closely, the field had already won.