A circular enclosure, the kind of enclosed farmstead or defended settlement built across Ireland from the early medieval period onward, once occupied this ground. It was recorded on the Ordnance Survey map of 1838, which means that at some point in the nineteenth century it was still visible enough to a surveyor to be worth marking. Sometime between that survey and the present day, it was levelled entirely. No surface traces remain.

Circular enclosures of this type, often called raths or ring-forts depending on their construction, were built in considerable numbers across Ireland, with estimates suggesting tens of thousands once existed. They served as enclosed farmsteads, their earthen banks providing both a boundary and a degree of protection for a household and its livestock. The example at Kiltarsaghaun is documented in a 1994 archaeological survey of the Ballinrobe district, which takes in the area around Lough Mask and Lough Carra. That record notes the site's position and its appearance on the 1838 map, and confirms what is now the defining fact about it: there is nothing left to see.

There is a particular kind of significance in a site like this. The 1838 Ordnance Survey was a remarkably thorough cartographic exercise, and the fact that surveyors recorded this enclosure at all suggests it was still a recognisable feature of the landscape at that time. Its subsequent disappearance, through agricultural improvement, land clearance, or simple erosion, is a common enough story in Irish upland areas, but no less pointed for that. What the map preserves is, in effect, the last reliable witness.