The builders of Carrickadaugh Rock did not simply choose a defensible spot and build walls around it; they cut the rock itself back by several metres to create an artificial cliff face, effectively weaponising the landscape against anyone attempting to enter from the south. It is the kind of deliberate, labour-intensive modification that tends to get overlooked when the drystone walls above ground steal most of the attention.

The structure is what archaeologists classify as a cashel, a stone-walled enclosure broadly equivalent to a ringfort but built in drystone rather than earthen bank. This one sits at the edge of a cliff-top promontory jutting westward from a west-facing slope, with the ground falling away steeply by as much as 30 metres from south-east to north-north-east. The fort is roughly subcircular, measuring about 31 metres north to south and 25 metres east to west. Where the natural rock-face is steepest, from the south-west around to the north-north-east, the builders applied stone facing roughly two metres high directly onto the cliff, cutting the rock back in places to seat it properly. A berm, a narrow level shelf of ground, runs along the base of this facing. On the gentler north-north-east to south-east arc, where the terrain offered less natural protection, a drystone wall about a metre high was built instead, with a wide level berm of around ten metres extending outside it. The promontory also contains a souterrain, an underground stone-lined passage of the kind commonly associated with early medieval settlement in Ireland, which sits partly within the southern edge of the fort and partly outside it. By the time of an inspection in 1998, dense blackthorn scrub and dangerous terrain prevented a full survey of the site, leaving parts of the structure formally unrecorded. The promontory appears under the spelling 'Carrickadaugh Rock' on Ordnance Survey maps from both 1840 and 1920, suggesting it was a known local landmark long before any archaeological attention found it.