The earthwork that once occupied this spot has been levelled so thoroughly that by 1970 observers could find no surface remains whatsoever. What survives today is stranger and more elusive than any earthen bank: a faint suboval cropmark, the kind of ghost that only appears from the air when differential moisture in the soil betrays the buried outline of something that was once substantial.

The 1837 Ordnance Survey Fair Plan marked the site plainly as a 'Fort', depicting it as a roughly circular, tree-planted enclosure, the ring of trees presumably serving as a boundary planting around whatever earthwork lay inside. By the time of the revised 1913 Ordnance Survey 25-inch map, the feature was recorded as an oval-shaped earthwork, measuring approximately 48 metres on its north-east to south-west axis and 45 metres north-west to south-east, large enough to suggest a ringfort of some significance. A ringfort, broadly speaking, is a circular or oval enclosure defined by one or more earthen banks and ditches, used during the early medieval period in Ireland as a farmstead or place of habitation. Roughly 50 metres to the north-north-west lies a related monument, a ringwork, a type of enclosure more closely associated with Norman defensive construction, suggesting this corner of Clonlost was something of a focal point across different periods of occupation. Somewhere between 1913 and 1970, the earthwork was erased from the landscape entirely, leaving that barely perceptible cropmark as its only remaining signature.