This is a cashel, the Irish term for a ringfort built from stone rather than earthen banks, and the example at Ballyganner is a quietly detailed one, measuring roughly 25.6 metres east to west and 22 metres north to south. The outer wall-face is notably well preserved, composed of large horizontally laid stones and still standing between 0.6 and 1.7 metres in height on the exterior. Two sets of vertical joints are visible in it, one at the south-west and another at the north-north-west, suggesting repairs or phased construction at some point in the structure's life.

The cashel sits within a large multiperiod field system, meaning the land around it was divided and worked across several distinct periods of history, and the enclosure itself was already old enough to be mapped when the Ordnance Survey produced its 25-inch plan in 1897 and its revised 6-inch map in 1920. Inside the walls, the ground holds further complexity: a grass-covered cairn runs from the north-north-east toward the south-east, with a larger cairn at its southern end, and two curvilinear banks extend outward from the wall at the west. A possible stone-lined drain is visible in the wall spread at the south-east. Against the outer wall at the north-east, a small later structure, recorded as a sheepfold on the 1897 map and measuring roughly 2 metres long by 1.3 metres wide, was built directly onto the ancient masonry, its northern side now collapsed. About 104 metres to the east lies a fulacht fia, a type of prehistoric cooking site typically identified by a mound of fire-cracked stone, often associated with water and communal or ritual use, which suggests this part of the Burren was a focus of human activity across a long stretch of prehistory.