It never appeared on any historic Ordnance Survey maps, and for decades its full story remained incomplete for a particularly poignant reason: the archaeologist who excavated it died before he could write up his findings. What survives is a structure of two rough stone kerbs set directly on natural rock, with loose pebble fill between them, enclosing an area of about 26.5 metres north to south and 24 metres east to west. The western boundary is not a built wall at all but the cliff face itself, a rocky ledge that drops away to another excavated site directly below.

Professor Seán P. Ó Ríordáin led eighteen seasons of excavation at Lough Gur, one of the most archaeologically dense landscapes in Ireland, and he dug this site, recorded as Site 12, in 1954. His untimely death meant no formal report was ever completed, and the surviving archive is, as Dr Eoin Grogan and Professor George Eogan noted in 1987, unusually thin: no plans or sections of the site survive. What Grogan and Eogan were able to reconstruct from the records describes a shallow deposit, averaging only about 0.2 metres deep even on the level western side, with slightly deeper accumulations in natural rock crevices. It was from those crevices that the most telling finds came: animal bones, flint scrapers, leaf-shaped arrowheads, and pottery classified as Western Neolithic, sometimes called Class I ware. On that basis, occupation of the enclosure is dated to around 3000 BC. There was no identifiable entrance, and no structural features beyond the wall itself, though aerial photographs taken in 1966 and 1968 show the enclosure outline clearly, and orthoimagery from 2011 to 2013 suggests the faint remains of a circular hut, about 6.5 metres in diameter, abutting the inner eastern wall.

Knockadoon Peninsula is accessible from the village of Lough Gur, where visitor facilities and signage help orient newcomers to what is genuinely one of Ireland's most layered prehistoric landscapes. The enclosure sits within a cluster of excavated sites; Circle K lies roughly 60 metres to the northeast, and several other excavated features occupy the surrounding slopes. The rocky, uneven ground on the eastern side of the enclosure means the terrain rewards careful footing. For those who prefer to examine the structure remotely first, a three-dimensional model of the site is available at skfb.ly/oswvD, which gives a useful sense of the topography before visiting in person.