A cashel, in Irish usage, is a stone-walled ringfort, and this one on the east-facing slope of a rocky ridge above Caherbullog is notable less for grandeur than for the questions it quietly raises. Within its interior, traces of small stone structures survive, including what the antiquarian T. J. Westropp described as "two of those puzzling little huts" with internal dimensions of barely a metre to a metre and a half. The walls enclosing them are double-faced, built with an outer and inner skin of undressed stone and a rubble fill between, a construction technique common across early medieval Ireland but rarely so legible in a site of this modest scale.

When John O'Donovan passed through in 1839 during the Ordnance Survey's mapping of Clare, he recorded the place as "Caher-Bolg", noting that "two cahers together" gave the townland its name. The companion enclosure is recorded separately nearby. By the turn of the twentieth century, Westropp had measured the main cashel at roughly thirty metres in diameter, with walls around three and a third metres thick and just over two metres high, though he judged it "coarsely built" and "featureless". Closer inspection reveals a more complicated structure. The enclosing wall is widest in the north-northeast, reaching around four and a half metres, and the outer face reaches two metres in height towards the south-east. Sections of the wall appear to have been rebuilt, and there are two gaps in the circuit: a poorly defined one to the north-north-west and a narrower later break to the south-south-east. A rectangular enclosure and a later stone structure abut the cashel's northern exterior, suggesting the site continued to attract activity well after its original construction. Field walls have also grown up against its perimeter over the centuries, weaving the ancient structure into the working agricultural landscape around it.