A small, circular area once defined by an earthen bank, it leaves no visible surface traces today, making it one of those quietly disquieting entries in the archaeological record: a place that is documented, mapped, and categorised, yet practically invisible to anyone standing in the field.

What little is known comes from the Ordnance Survey map of 1838, which recorded the enclosure at a time when some trace of it was apparently still legible in the landscape. Circular earthen enclosures of this kind are common across Ireland, and they range enormously in age and function. Many are the remains of raths or ring-forts, the enclosed farmsteads of early medieval Ireland, in which an earthen bank and ditch defined a domestic space for a family and their livestock. Others are earlier still. Without excavation, it is impossible to say what Rathnaguppaun's enclosure once contained or who built it. By the time the nineteenth-century surveyors noted it, the bank was presumably reduced enough to warrant attention but not so eroded as to escape notice entirely. Sometime in the century and a half since, it faded below the threshold of visibility altogether.