Not obscured by vegetation or tucked behind a wall, but genuinely invisible at ground level, detectable only as a faint shadow in the historical record. That record is the first edition Ordnance Survey six-inch map, which captured the site as a semicircular enclosure at a moment when it was apparently still legible in the landscape. Sometime between that survey and the present, it disappeared entirely from view.

Semicircular enclosures of this kind are relatively uncommon in Irish archaeology. Where circular or roughly oval ringforts, known in Irish as raths, were built as enclosed farmsteads throughout the early medieval period, a semicircular form sometimes indicates that a natural feature, a slope, a stream bank, or a ridge, was incorporated into the boundary, reducing the labour of construction. The setting here, on rising ground in an upland area, is consistent with that kind of practical arrangement. A second enclosure survives nearby to the north-east, suggesting this part of the townland was once more densely occupied or organised than the present emptiness implies. Whether the Lisdalleen and Drummin earthwork was ploughed out, eroded, or simply subsumed into later agricultural activity is not recorded.