At Keereen in County Waterford, there is a circular earthwork that you could walk directly across without knowing it was there. Roughly 35 metres in external diameter, this embanked enclosure sits in pasture on a south-facing slope at the head of a small east-west valley, and it is, according to the record, simply not visible at ground level. The land gives nothing away.

The enclosure first appears on the Ordnance Survey six-inch map of 1840, one of the earliest systematic cartographic surveys of Ireland, which captured features across the landscape that local knowledge had long registered but that no one had previously committed to a standardised national map. Embanked enclosures of this kind are generally understood to be early medieval in origin, constructed as enclosed settlements or farmsteads, with an earthen bank defining a roughly circular boundary. They are related to the more familiar ringfort type, though the term tends to be applied where the defining feature is a low bank rather than a pronounced raised rath with external ditch. What makes the Keereen example quietly odd is not its form but its near-total invisibility. The valley setting and the gradual degradation of the bank over centuries have left a monument that survives on paper, and in the ground as a subtle undulation, but that has effectively withdrawn itself from the visible world.