On the northern slopes of a hill in the undulating farmland around Doon in County Galway, there was once a circular enclosure roughly twenty metres across. It is recorded, it has a category, and it has coordinates. What it does not have is anything you could actually see.

The site appears on the Ordnance Survey six-inch maps, those remarkably detailed nineteenth-century surveys that captured the Irish landscape at a moment when a great deal of earlier archaeology was still legible at ground level, if only barely. The cartographers noted a circular enclosure, the kind of earthwork that in Ireland typically signals early medieval activity, a period running roughly from the fifth to the twelfth century, when enclosed farmsteads known as raths or ringforts were a common feature of the countryside. Such enclosures were usually defined by one or more banks and ditches, protecting a household and its animals. The one at Doon measured around twenty metres in diameter, which is modest even by the standards of smaller examples. At some point between the map-makers passing through and the present day, whatever surface trace remained was lost entirely, ploughed away or otherwise erased by the ordinary work of farming the land.