On a hilltop in County Kildare, there may once have stood a substantial double-walled enclosure that has since slipped almost entirely from the historical record. It appears clearly on Taylor's Map of Kildare, dated 1783, drawn on top of Ballyvoneen Hill and described as bivallate, meaning it was defined by two concentric banks or walls rather than one. That double circuit is a feature often associated with sites of some significance, whether defensive, ceremonial, or territorial. Yet when the Ordnance Survey came to map the same ground in the nineteenth century, the enclosure was gone from the record entirely, absent from every edition of the OS six-inch maps. It neither vanished from the landscape nor entered the official cartographic tradition; it simply fell through the gap between the two.

Taylor's Map of Kildare, produced by George Taylor in 1783, was a county survey of the kind common in late eighteenth-century Ireland, generally reliable in its broader outlines but not always consistent in the detail it chose to record. The fact that Taylor's surveyors noted a bivallate enclosure here at all suggests something was visible and legible on the hilltop at that time. Why the Ordnance Survey later omitted it is unclear. The feature may have been partially levelled or obscured by the early nineteenth century, or it may simply have been overlooked. What survives today, if anything survives, is ambiguous. Modern aerial imagery shows what might be a partial outline in the area, though the traces are faint enough to leave the question open. A trigonometrical station, one of the benchmark points used by the Ordnance Survey to fix precise elevations across the country, is marked at this location on a revised edition of the six-inch map, which at least confirms the hilltop itself retained some cartographic relevance even after the enclosure disappeared from the record.