Caer Caradog is a later prehistoric type hillfort crowning an isolated mountain spur overlooking the Cerrigydrudion valley basin. It was partly excavated in 1963 and 1964.
The hillfort is an irregularly oval enclosure defined by a massive rampart and ditch with a counterscarp bank beyond. The rampart still rises some 6.0m above the base of the ditch. Excavation showed it to be of a simple dump construction. There is an entrance to the east facing along the saddle connecting the spur to the main massif of Y Drum. This enclosure is about 166m east-west by 130m, with an area of 1.7ha.
There are slight remains of a concentric inner circuit, surveyed in part in 1963-4 and fully outlined on the 1st edition OS County series (Denbigh. XXXII.1 1875). It crowns the actual summit of the spur. This circuit is comparatively slight and at one point was shown to rest on a 'flimsy' boulder base 2.3m wide. It is roughly 122m east-west by 89m, with an area of 0.8ha. RCAHMW aerial coverage shows cultivation ridges within this inner circuit and it may be a comparatively recent agricultural enclosure, possibly a rabbit warren.
The excavations failed to identify any structures apart from the ramparts; notably no trace of a gate was recorded. This gave rise to doubts about the identification of the Caer as a hillfort as such. However, it is possible that any features present were missed.

Source: Smith & Livens in Archaeologia Cambrensis 140 (1991), 77-101

John Wiles 13.12.07; updated by T. Driver, RCAHMW, 3rd Feb 2011