At Carrickagarvan in County Monaghan, a low-lying landscape of gentle slopes once held a roughly oval earthwork, somewhere in the region of thirty metres across, defined by a modest bank of earth and stone. By the time anyone thought to look closely, it was already almost gone.

The site appears on the 1834 edition of the Ordnance Survey six-inch map, marked in gothic lettering as a 'fort', the convention used to indicate an enclosure of presumed early medieval or prehistoric origin. These earthwork enclosures, often called ringforts, were typically used as enclosed farmsteads, defined by a circular or oval bank, and sometimes a fosse, which is a surrounding ditch. At Carrickagarvan, no fosse was ever identified, and no clear entrance was recorded either. When field investigators visited in 1984, only slight traces remained: a bank barely a metre wide and half a metre high, running along the eastern, south-western, and north-western arcs of the oval. Within eleven years, even that was gone. Quarrying had removed the enclosure entirely by 1995, leaving nothing on the ground to correspond to that gothic inscription on the old map.

What makes Carrickagarvan worth noting is precisely the gap between the 1834 map and the 1995 reality. The site existed in the record long enough to be counted, measured, and partially described, then vanished before any more detailed investigation was possible. It is the kind of place that reminds you how much of the Irish archaeological landscape has been lost not to dramatic events but to the slow accumulation of ordinary decisions about land and stone.