That absence is precisely the point. What once stood here, a circular enclosure roughly twenty to twenty-five metres across, was recorded on the Ordnance Survey's six-inch map of 1837 to 1838 and then, by the time the 1922 edition was produced, had simply vanished from the cartographic record. Whether it faded from view gradually or was already gone by the early twentieth century, no visible surface remains survive today.

Circular enclosures of this kind are a familiar feature of the Irish landscape, earthwork or stone boundaries that in different periods served as farmsteads, ceremonial spaces, or enclosures for livestock, commonly referred to as ring-forts or raths when they are of early medieval date, though earlier prehistoric examples also exist. What the Carrownaglogh enclosure actually was, its age and purpose, remains unknown. What can be said is that the southeastern portion of the knoll was disturbed by quarrying in the early 1990s, which will have removed or displaced whatever subsurface traces remained in that area. The knoll itself still commands very good views across the surrounding countryside, which may well explain why someone chose to build here in the first place. High ground with wide sightlines was consistently valued, for defence, for surveillance of livestock, or simply for the practical advantage of seeing who or what was approaching.