Environment Agency archived LiDAR data shows the survival of a small hillfort on the partly wooded hillock of Bryn-Dinas in Happy Valley/Cwm Maethlon. The hillfort is an elongated oval in plan, measuring 242m east-west x 68m, enclosing 1.3 hectares. The northern escarpment of the hillock is defined by scarp slopes where the terrain is steepest. On the east, west and south sides a single rampart defines the enclosure. At the central point of the southern rampart there is a secondary rampart set apart from a break in the inner, suggesting a gateway here with a protective outwork, guiding approaching traffic up from the valley floor to the south-west. While the central part of the hillock is free of trees, the surviving ramparts and hillslopes are wooded, with the prehistoric earthworks only cleared revealed on the LiDAR Digital Terrain Model.

T. Driver, RCAHMW, 19 April 2017