On a gentle south-facing slope in Ashtown, County Waterford, a low earthen bank curves around a scrub-covered patch of ground in a shape that is almost, but not quite, a circle. The western side runs conspicuously straight, flattened or absorbed at some point by a field boundary running north to south, which gives the whole enclosure a distinctly D-shaped outline when viewed from above. The bank itself is modest, between three and four metres wide and no more than half a metre high in places, planted along its length with coniferous trees. There is no visible fosse, the defensive ditch that typically accompanies earthworks of this kind, and no identifiable entrance survives. What exactly this place was built for remains, as with so many such sites, an open question.

What makes this enclosure quietly puzzling is the disagreement between the historical maps that record it. The Ordnance Survey six-inch map of 1840 shows a subcircular enclosure with external dimensions of roughly twenty-five to thirty metres. By the 1926 edition of the same map, it has been recorded as a circular enclosure with an external diameter of around forty-five metres, a significant difference that may reflect changes on the ground, different surveying methods, or a degree of interpretation on the part of the cartographers. The enclosure as it exists today measures approximately thirty-two metres north to south and twenty-eight metres east to west. Embanked enclosures of this general type are found across Ireland and are often associated with early medieval settlement or land use, though without excavation it is rarely possible to say more than that. This one does not stand alone in the landscape: a related earthwork lies roughly fifty metres to the south, and a rath, a type of circular earthen ringfort used as a farmstead enclosure in the early medieval period, sits about a hundred and fifty metres to the north-east, suggesting this corner of Waterford was once a busier place than it now appears.