What survives is a poorly preserved rectangular structure, roughly 40 metres by 34 metres, its south-western side still doing quiet duty as a boundary between Ballyallaban and the neighbouring townland of Gragan East. The working suspicion among those who have studied it is that this is the remnant of a rectangular cashel, a type of early medieval stone enclosure typically associated with settlement or landholding, and a form well represented across the Burren.

The antiquarian Thomas Westropp noted the site in 1901, describing it at that time as a circular stone enclosure, or moher, some 117 feet across with walls 6 feet thick, and observing that it had been nearly levelled since 1895. Even earlier, the first edition of the Ordnance Survey six-inch map, published in 1842, recorded what appeared to be a square enclosure of roughly 32 metres on each side on the same ground. The discrepancy between the circular form Westropp described and the rectangular outline visible today may reflect the complexity of the site's history, or simply the difficulty of reading badly degraded stonework. What complicates matters further is the enclosure's relationship to its neighbours: it appears to partially overlie the outer wall of the large bivallate cashel known as Cahermore, meaning it may post-date that structure, and it sits immediately north-west of a second, smaller cashel. Bivallate cashels have two concentric enclosing walls, and Cahermore is among the more substantial examples in the region. To have a third enclosure apparently layered across one and adjacent to another suggests a long and untidy sequence of activity in a relatively small area of ground.