On a broad, low plateau in Graigavalla, County Waterford, there is an enclosure that has no visible way in. It is roughly circular, measuring about 25 metres east to west and 22 metres north to south, and its boundary is not a wall or a ditch but a slight scarp, a low step in the ground between five and seven metres wide and no more than twenty centimetres high. Walk across it and you might not notice it at all. That near-invisibility is part of what makes the site quietly compelling.

The enclosure appeared, already faint, on the Ordnance Survey six-inch map of 1840, which means it was old enough by the early nineteenth century to have settled into the landscape rather than standing out from it. Circular and subcircular enclosures of this kind are found across Ireland and can date from the prehistoric period through to the early medieval, sometimes serving as settlements, sometimes as enclosures for livestock, and occasionally as ritual or ceremonial spaces. Without excavation it is impossible to say which category this one belongs to, and the absence of an entrance only deepens the uncertainty. Either the entrance has been lost to centuries of erosion and farming, or it was never the kind of feature that left a mark at the surface.