Somewhere in the mixed woodland fringing the southern edge of Rathangan Demesne, a low earthen bank traces an almost perfect square in the ground, quietly ignored by the landscape around it. It is not a dramatic feature; the interior sits only slightly raised, the bank itself rises barely a metre on its outer face, and the shallow fosse, a ditch encircling the outside, is little more than a gentle depression. Yet the geometry is deliberate, and the question of what it enclosed, and when, has no obvious answer.

What makes the site particularly curious is its relationship with the maps. When the Ordnance Survey recorded this part of County Kildare for their first six-inch edition in 1838, the enclosure did not appear, and the ground was open rather than wooded. By the time the revised edition was published in 1910, trees had colonised a narrow strip along the townland's southern boundary, and the feature was recorded within that new woodland. It is possible the enclosure predates both maps by centuries, concealed or simply missed in 1838, and only noticed once the tree cover gave surveyors reason to look more carefully. The earthwork measures roughly 28 metres north to south and 26 metres east to west internally, with a surrounding bank about two metres wide. An enclosure of this kind, defined by a raised bank and outer fosse, is a form found across Ireland in contexts ranging from early medieval settlement to later agricultural or ornamental use, and nothing in its current condition settles the question of its origins.

The site lies approximately ten metres north of a small westward-flowing stream, in mixed woodland that has grown up around it over the past two centuries at least. The earthwork is poorly preserved, so picking out its edges requires some patience once you are among the trees.