J. Westropp first drew attention to it in the 1890s: a narrow internal staircase, cut into the thickness of the enclosing wall, which he called a 'stone ladder'. Six recessed steps, each just 0.8 metres wide, gave access to a terrace running along the inner wall-face, and from there a further flight of four steps once led to the top of the wall itself. By the time Westropp returned to write up the site more fully in 1913, the upper steps had been nearly destroyed, and when the cashel was inspected again in 1999 that second flight was no longer visible at all. The main enclosure itself survives well: a roughly circular wall between 2.4 and 3.6 metres thick, still standing to an external height of up to 2.3 metres, surrounding an interior roughly 29 metres across.

The site sits on fairly level, overgrown karst limestone in the south-eastern area of the Burren, Co. Clare, and appears on the first edition Ordnance Survey six-inch map of 1842 under the name 'Caherahoagh Forts', a label that also takes in an adjacent cashel lying roughly 25 metres to the south-west. Later mapping renamed it 'Caherbullaun Forts', and Tim Robinson's 1977 map of the Burren gives the Irish form 'Cathair an Bhulláin', though Westropp consistently preferred Caherahoagh. The entrance, set into the east-south-east of the wall, is where the most telling architectural evidence lies. It splays outward from inside to outside, narrowing from 2.1 metres at the inner face to 1.55 metres at the outer, and its north side contains two draw-bar sockets placed one above the other, the kind of fittings used to secure a heavy timber door. Westropp concluded that this entrance had been rebuilt using dressed stone and mortar in the fifteenth century. Elizabeth FitzPatrick, writing in 2009, placed this reconstruction in a broader pattern of late-medieval upgrades to Burren cashels, noting that where some sites received a full gatehouse insertion, Caherahoagh instead received a cut-stone arch with punch-dressed jambs. The arch itself is gone, but a single dressed arch-stone was identified lying in the collapsed masonry just outside the entrance.

The interior of the cashel is now heavily tree-covered. Among the fallen wall stones and accumulated debris, a small rectangular drystone structure survives to the south of the entrance, measuring roughly 3 metres by 2.5 metres, and there are remnants of what may be a second stone building in the northern half of the enclosure. The trees make the space feel enclosed and slightly disorienting, which gives the drawn sketches Westropp made during his visits, showing the stepped wall-passage in clearer relief, an added value: they record a feature the vegetation now makes very difficult to read.