Where early nineteenth-century cartographers recorded a circular embanked enclosure some 35 metres in external diameter, the ground today tells a slightly different story: an oval, grass-covered hollow measuring roughly 26 metres from northwest to southeast and 18 metres from northeast to southwest. The enclosure, in other words, has inverted itself in the landscape, the raised bank that once defined it having slumped inward until what remains is more depression than definition.

The sole cartographic record of this feature as an enclosure comes from the 1839 edition of the Ordnance Survey six-inch map, one of the most systematic attempts to document the Irish landscape and its archaeological remains in the nineteenth century. By the time anyone looked again with a view to cataloguing it formally, only the hollow endured. Embanked enclosures of this kind are found across Ireland and can serve a range of functions depending on their age and context, from early medieval settlement enclosures to later livestock management features, though without excavation the specific purpose of the Glenduff example remains open. Its position just off the ridge crest, on a north-facing slope, is a modest but telling detail; such positioning can reflect practical concerns around drainage, visibility, or proximity to agricultural land.