At some point, the enclosure at Boolahallagh was deliberately levelled, and a field boundary that had stood long enough to appear on the 1904 revision of the Ordnance Survey six-inch map was removed in the same episode of clearance. Whatever the intention, the monument refused to disappear entirely.

What remains is a circular area roughly 26 metres in diameter, its enclosing bank reduced almost entirely to a low scarp, a gentle step in the ground rather than anything upstanding. The bank itself is about 3.5 metres wide, and while its internal height barely reaches 30 centimetres in places, the external face survives to just over half a metre in the most intact sections. A gap on the east-south-east side, around 4.5 metres across where the bank becomes indistinct, is thought to be the original entrance. Outside the bank, there are faint traces of a fosse, a shallow surrounding ditch, most readable in the northern, eastern, and western portions of the circuit, though it is slight throughout, no more than 13 centimetres deep. The interior of the enclosure tilts gently downhill to the east. Enclosures of this type are a common feature of the Irish landscape, typically interpreted as the remains of early medieval ringforts used for farming and habitation, though without excavation the function and date of any individual example remain uncertain.

The site sits just below the crest of the slope, which likely contributed to its partial preservation. Earthworks in elevated positions often escape the worst of deep ploughing, and even a flattened monument can hold its shape in pasture ground where the soil has not been repeatedly turned. Here, the surviving topography is subtle enough that it would be easy to walk across the enclosure without recognising it, but once you know the diameter and the slight change in level underfoot, the circular logic of the place becomes legible.