1. On the summit of Skirrid fawr is an elongated enclosure measuring roughly 320m north-south by 100m, tapering to a point on the south, and apparently defined by a continuous bank/scarp. It occupies the summit of an isolated, mountainous ridge (Nprn605). Source: Makepeace, Archaeology in Wales 36 (1996), 66-8.
Within the enclosure, on the north, is a medieval chapel site (Nprn306440).
RCAHMW, February 2011
2. The prominent Ysgyryd ridge is almost fully enclosed by a series of two or three defended ridge-top enclosures, identified both from Royal Commission aerial reconnaissance and LiDAR data. The northern two enclosures are scheduled monuments but LiDAR adds further detail, showing an extension of the central enclosure or perhaps a far earlier monument to the south. Relative phasing of the earthworks suggests a progression of enclosure from south to north, with the northernmost summit enclosure being the latest. Overall the earthworks enclosing the narrow ridge and northern summit of Ysgyryd run for 700m north-south, enclosing 5.70 hectares. In character they suggest an early ridge-top enclosure/s dating to the Neolithic or Bronze Ages, superceded in the Iron Age by a commanding northern summit settlement.
Such a prominent ridge may never have been enclosed for year-round settlement, and may indeed have been intended for sacred or ceremonial use, or regional gatherings at a highly visible location.
Northernmost summit enclosure: An oval defended enclosure measuring 201m N/S by 85M E/W, enclosing around 1.53 ha. LiDAR shows a series of construction quarries behind the rampart on the east side, with lines of house platforms above shelved into the steep eastern hillslopes. There appears to be a gateway defined by earthwork terminals at the southern tip of this enclosure.
Central ridge-top enclosure: The northernmost enclosure overlies earlier earthworks of a defended ridge-top enclosure which occupies the central part of the ridge. It measures 62m across and is crowded with rock-cut house platforms particularly along the eastern side. Approx 150m south of the gateway to the northernmost enclosure, this central enclosure kinks to the west; this appears to be where it overlaps with a third southernmost ridge enclosure; however the earthworks may all represent part of one much larger enclosure.
Southernmost ridge-top enclosure: Extending some 340m south of this 'kink' in the earthworks is a potential third enclosure, measuring 60m across at its widest point and tapening to a narrow southern gateway. This enclosure also has a number of internal platforms visible on LiDAR data.
Dr Toby Driver, RCAHMW, May 2025