Roughly subcircular in shape, measuring around 40 metres north to south and 35 metres east to west, it was recorded on the Ordnance Survey six-inch maps as a slightly oval, tree-planted feature. What those maps show and what survives on the ground are now quite different things. A modern field boundary cuts across it at the north-north-east and south-south-west, and nothing at all remains to the west of that boundary. To the east, a narrow fosse, essentially a shallow ditch, traces a semicircular arc roughly 35 metres long and about a metre wide. The interior is uneven beneath its grass cover, and a small pond sits 25 metres to the north.

The uncertainty around this site is itself the interesting part. It may be no more than a designed landscape feature, the kind of ornamental earthwork that demesne owners across Ireland occasionally added to their grounds during the eighteenth and nineteenth centuries. But the surrounding land complicates that reading. The Castlegar demesne contained several ringforts, the circular enclosures of raised earth that served as defended farmsteads in early medieval Ireland, and two of them lie to the south-east. A monument of similar character sits just 80 metres to the south. That density of related features suggests the enclosure may belong to an older pattern of settlement rather than to any landlord's sense of aesthetics, though without excavation the question remains genuinely open.