The circular fort at Ballybreen sits on a south-south-east-facing slope with open views to the south, embedded within a wider field system that shows evidence of use across multiple periods. Two modern gates have been set into the east and west walls, and a concentric wall running about four metres outside the main enclosure perimeter forms a narrow avenue that appears to serve as a livestock-handling passage. It is a quietly matter-of-fact repurposing of something old.

The structure itself is a roughly circular enclosure, with internal dimensions of about 25.75 metres, of the kind broadly known as a ringfort, an enclosed farmstead or dwelling type that was common in early medieval Ireland. The boundary is defined by the collapse of an original wall, now grassed over to a width of about a metre, with a later drystone wall, standing 1.5 metres high, built on top of it. Inside, along the eastern wall-face, two small alcoves survive, each roughly a metre long and a metre wide, though both are partly blocked up. The interior slopes gently southward. A curving outer bank, seven metres wide and 0.8 metres high, sweeps from south to west at a distance of roughly 33 metres from the south wall and 14 metres from the west, suggesting the site once had more elaborate outer earthworks than are immediately obvious on the ground. The fort was already considered significant enough to be hachured and named on the Ordnance Survey six-inch map of 1842, and it appears again on the 25-inch edition of 1897, where it is shown as an incomplete circle, open to the north-north-west, a gap that has never been fully explained.