That cartographic oddity is one of the first hints that this place has been somewhat misread across the centuries. It sits on a north-east-facing slope near a rocky cliff in the townland of Dangan, half-swallowed by scrub at the edge of reclaimed pasture. The surrounding high ground closes in on most sides, but through a craggy gap to the north-west there is a long view out to Galway Bay, and to the west-south-west the Rath of Ballyallaban and the Aghaglinny valley come into sight.

The cashel itself is roughly circular, with an internal diameter of just over twenty-five metres. Its wall, built from undressed and uncoursed limestone slabs laid flat, still stands to an external height of up to two metres in places, and along the north-west to north arc there is a possible internal terrace that the antiquarian Thomas Johnson Westropp, writing in 1901, described as paved with thin slabs. The east-facing entrance is where the site becomes particularly interesting. When Westropp recorded it at the turn of the twentieth century, each side was lined by three orthostats, upright standing stones, and the whole was capped by two massive lintels each roughly two and a half metres long. By the time of later inspection, that arrangement had been reduced: only one upright remains in position on the south side, standing 1.32 metres high, with its counterpart on the north side displaced. Beneath the interior, south of centre, lies a souterrain, an underground stone-lined passage of the kind often associated with early medieval settlement and used variously for storage or refuge. Westropp also identified the site as very likely the "Cahernagree" mentioned in seventeenth-century documents, including the Book of Distribution, which names one Dominick Lynch of Kahirnegree as a local landowner, suggesting the cashel retained enough presence on the landscape to anchor place names and property records long after it had ceased to function as a settlement.