It looks, at first glance, like a ringfort, the kind of raised, embanked enclosure that early medieval farmers and landowners built across Ireland in their thousands. But when surveyors consulted the 1837 edition of the Ordnance Survey six-inch map, they found it recorded not as an ancient monument but as a landscaped tree-ring, a deliberate ornamental feature of the castle demesne. That single cartographic detail transforms the whole reading of the place.

The ambiguity runs deep. One possibility is that an original ringfort, already ancient by the eighteenth century, was absorbed into the landscaping programme of the Ballinlough Castle estate and dressed up as a decorative circular planting. The other is that the feature was constructed from scratch after 1700, shaped to resemble an ancient earthwork as part of the fashionable demesne design of the period, when landowners across Ireland and Britain sometimes built artificial mounds and enclosures to lend their grounds a pleasing antiquarian atmosphere. What survives today is a very large, slightly raised circular area enclosed by an earthen bank and a wide, steep external fosse, the ditch that would typically surround a defensive or enclosing structure. The bank has been levelled and the fosse filled in along the south-west to west arc, damage consistent with agricultural tidying or deliberate alteration. Inside, in the south-east quadrant, a low mound about six metres across and less than a metre high is still visible. A further ringfort lies just 130 metres to the north-north-east, which adds a layer of plausibility to the idea that this landscape was already marked by earlier settlement before any estate designer arrived.