On a slope above the Finisk River in County Waterford, a perfectly circular patch of grass sits enclosed by earthworks that have no clearly identifiable entrance. That absence is one of the more quietly puzzling things about the embanked enclosure at Ballynaguilkee. A wide gap does exist in the inner bank on the western side, but whether this represents a collapsed or deliberately removed entrance, or something else entirely, remains an open question.

The enclosure measures forty metres across in both directions, forming a neat circle defined by a substantial earthen bank roughly seven metres wide. The bank survives to a height of between one and one point seven metres on its exterior face, though it has been worn down to little more than a scarp on the north-east arc. Around the outside runs a U-shaped fosse, the term for a defensive or boundary ditch, up to a metre deep and seven metres wide at its opening, which extends around the eastern and north-western sides. Beyond that sits a further external bank on the south to south-west, adding a third layer of definition to what is already a carefully structured arrangement of earth and hollow. The whole thing faces east, sloping gently down toward the Finisk River about a hundred metres to the south-east. Enclosures of this general type, circular earthworks with banks and ditches, appear across Ireland in various forms and periods, sometimes associated with settlement, sometimes with ritual or assembly, and sometimes their original purpose simply cannot be determined from what survives above ground.

The grass covering the interior and banks suggests the site has remained undisturbed for a long time, which has helped preserve the subtle topography of the earthworks. Visiting in low winter light or after a dry summer, when shadows and parched grass reveal differences in ground level that are otherwise invisible, tends to make the concentric rings of bank and fosse much easier to read from the ground.