A circular embanked enclosure, roughly 30 metres across, was recorded on the Ordnance Survey six-inch map of 1838, drawn during one of the most ambitious cartographic exercises ever undertaken in Ireland. By the time later map editions came to be produced, it had vanished from the record entirely, and today there is no visible trace at ground level. The earthwork has been levelled, absorbed back into the undulating pasture that rolls across the limestone terrain, the break of slope falling away to the south-west as though nothing was ever marked here.

What the 1838 surveyors recorded was almost certainly a rath, or at least something closely related to one. A rath is a roughly circular enclosure defined by an earthen bank and ditch, typically dating to the early medieval period in Ireland, and used as a farmstead or place of habitation. The form at Lismiraun, described as a circular embanked enclosure of around 30 metres in diameter, fits comfortably within that tradition. A confirmed rath survives 150 metres to the north-west, which gives some sense of what this landscape once held: two enclosures in close proximity, suggesting a pattern of early settlement across this part of Mayo that has since been almost entirely erased by centuries of agricultural use. The fact that one survives and the other does not is, in its own quiet way, the more telling detail.