'Braich y Dinas, an important hill-fort on Penmaen Mawr, now entirely destroyed. The site was examined by H H Hughes and the following account is based on his reports.
The hilltop was defended by massive ramparts of roughly coursed rubble masonry, with no orthstats. These still stood in places to a height of 9 ft., and varied from 8 to 15 ft. in thickness. The number and character of the entrances were uncertain. The interior contained 90 or more huts of various shapes but mostly oval with a usual diameter of 10-20 ft. Their walls were of similar construction to the rampart, about 5 or 6 ft. thick, and stood in places to a height of 4 ft.
All dateable objects can be assigned to the period AD 100-400, and no evidence was found to indicate more than one period of contruction. The evidence of the relics suggests that the most prosperous inhabitants of the fort were those living between the outer and middle ramparts, as all the Samian pottery, and four of the six coins found, came from this part of the fort. The site produced saddle querns, but none of the rotary type'.

Extract from RCAHMW 1956, An Inventory of the Ancient Monuments in Caernarvonshire, Volume 1: East, pages 85-86, site 252.

It is worth noting, on inspection of the site plan produced before the hillfort was destroyed (Figure 85), that the assumption of a single phase of construction and occupation based on the recovered finds is very likely to be inaccurate. The plan of the fort shows a smaller summit-top enclosure, with potentially successive phases of annexes and additional enclosures added to the original spreading down the hillslope to the south and south-east. It is likely that this complex fort was long-lived. Summit top cairns are also noted on the plans which may have been early Bronze Age.

T. Driver, RCAHMW, 9 Sept 2011