In a pasture at Lerrig in County Kerry, a small circular enclosure, roughly twenty metres across, was recorded on the first edition Ordnance Survey six-inch map of 1841, drawn as a bank enclosing a roughly circular area of ground. By the time later map editions were produced, it had already vanished from the cartographic record entirely. When the site was inspected in 2000, the field offered nothing visible at surface level, no trace of a bank, no depression, no shadow in the grass.

The 1841 Ordnance Survey maps, produced during the first systematic large-scale mapping of Ireland, captured the landscape at a particular moment, and in doing so preserved evidence of features that were already disappearing or would soon do so. Circular earthwork enclosures of this general type are common across Ireland and are frequently associated with early medieval settlement, the most familiar being the ringfort, known in Irish as a ráth or lios, which typically consisted of a raised bank and sometimes a fosse enclosing a domestic space. Whether the Lerrig example belonged to that tradition or represented something else entirely is now impossible to say with confidence. What the 1841 map recorded, later agriculture or land improvement appears to have removed, leaving only the cartographic trace as evidence that something was once there.