The low, grassy bank that traces an irregularly circular perimeter across the SE-facing slopes of a steep ridge was first built, according to radiocarbon dating, somewhere between 1200 and 931 BC, during the Late Bronze Age. That a later generation simply incorporated it into the fabric of ordinary land division, and that the 1840 Ordnance Survey mapped it without particular comment, gives some sense of how thoroughly the prehistoric can be absorbed into the mundane.

The enclosure is substantial. Its external diameter runs to roughly 148 metres at its widest, making it a genuinely large prehistoric monument, enclosed by a bank of earth and stone between five and six metres wide and just over a metre high internally. In 1985, Gibson excavated a section of the enclosing element and found a single phase of earlier wall construction: large upright slabs set in shallow sockets, faced on the outside with flat slabs and packed with stones of various sizes. Two radiocarbon dates from the foundation level confirmed the Late Bronze Age origin, while a third date, from just beneath the modern sod, placed further activity at the site in the Iron Age, around 486 to 280 BC. The interior is not a flat, uniform space; it slopes down from NW to SE across a series of natural stepped limestone terraces. Near the centre, a circle of stones and an L-shaped alignment both sit close to a large pit, which Gibson suggested in 2007 may relate to lead workings in the vicinity. A natural gully at the SE may mark the original entrance. Adding further complexity, a later cashel, the kind of stone-walled enclosure associated with early medieval settlement, was built directly against the southern perimeter, and it contains a souterrain, an underground stone-lined passage, that incorporates a natural cave. The whole assemblage sits within a wider, multi-period field system, and the Ballyconry enclosure is one of several comparable prehistoric enclosures known from across the Carran plateau, with a site of similar construction recorded roughly 1.8 kilometres to the northwest.