Yet that is precisely the scene conjured by the eighteenth-century poet Hugh MacCurtain, writing about a place he called the pinnacled house of the descendant of Roigh. The cashel at Formoyle, on the south-western foot of Gleninagh Mountain, is now barely legible in the landscape: a subcircular enclosure roughly 27 metres across, its once-substantial stone wall reduced to a grassed-over bank no more than half a metre high in places. A short arc of outer facing-stones survives on the western side, and a shallow rectangular depression in the north-west may be the collapsed remains of a souterrain, an underground passage or chamber of the kind often associated with early medieval settlement sites. A later field wall has been built directly across the bank, running west to east, which says something about how thoroughly the structure had faded from active memory by the time farmers needed the stone.

The naming of the place has puzzled antiquarians for well over a century. When John O'Donovan visited in 1839, he recorded it as Cathair Beannach, meaning the Pinnacled Caher, and noted it was already ruinous. A caher or cashel is a stone-walled ringfort, the enclosure type common across Munster in the early medieval period. By 1901, the scholar Thomas Westropp was arguing that the correct name should be Caheragh, pointing to its appearance as Cathrach in the O'Brien family rentals of around 1390 and as Cahera in the inquisition taken after the death of Donough, Earl of Thomond, in 1597. The confusion is compounded by the fact that two different editions of the Ordnance Survey six-inch maps assigned the name Caherbannagh to two different sites in this cluster: this cashel and a possible rectangular cashel roughly 240 metres to the north-west. MacCurtain's poem, with its image of a dove on a blackened ruin, may refer to either one. The identity of the descendant of Roigh, whoever lent the site its former significance, remains unresolved.

The site sits prominently on the western edge of a terrace of rough grazing, positioned to overlook both the Caher Valley and its river below. Within 250 metres there are at least three further related monuments, including a completely denuded ringfort to the south and two possible rectangular cashels to the north-west, suggesting this was once a meaningful concentration of settlement or enclosure activity rather than an isolated structure.