At Clomantagh in County Kilkenny, an ancient enclosure that survived long enough to be recorded on the first Ordnance Survey maps of Ireland in 1839 did not survive the twentieth century. By 1987, it had been levelled entirely, and what remains today is a landscape that gives no outward sign that anything was ever there.

The 1839 six-inch Ordnance Survey map, part of the earliest systematic cartographic survey of Ireland, recorded the feature as an oval enclosure measuring roughly 28 metres along a northeast-southwest axis and about 15 metres across. Such enclosures, typically formed by an earthen bank or raised ring, are common across the Irish countryside and are often associated with early medieval settlement, though their dates and functions vary considerably. By the time of the 1900 revision, the shape had been recorded somewhat differently, as a roughly circular enclosure of around 23 metres in diameter. Whether that reflects an actual change in the monument's condition or simply a difference in how the surveyor read the ground is impossible to say. What is clear is that two separate moments of destruction finished it off: quarrying cut away the northern portion, and a public road running east to west truncated the southern half. The combination left nothing standing.