The area of moorland (400m above sea level) between Hafoty Sion Llwyd and the Aber Llech Daniel on the eastern edge of the Brenig Reservoir was investigated by RCAHMW in 2009 as part of a wider study of the landscape surrounding the medieval vaccary (cattle ranch) of Hen Ddinbych (NPRN 303472). This is an area rich in archaeology, as revealed through excavations carried out between 1973 and 1975 prior to the flooding of the Brenig Valley to form the reservoir.

In the distant past the valley had been the home of Bronze Age farmers, who buried their dead beneath cairns and barrows, two of which lie within the study area, Waen Ddafad Cairn, Brenig 8 (NPRN 303466) and the platform cairn, Brenig 51 (NPRN 409201). In historic times this valley supported quite a large population of farmers, predominantly using the moors to graze cattle and sheep with the earliest feature associated with this exploitation a hollow way (NPRN 411903),that appears to define an early route/road across the moors, and which may be at least Medieval if not older in date. The medieval vaccary (cattle ranch) of Hen Ddinbych (NPRN 303472), is a relatively unusual monument and is associated with the monastic exploitation of the moors. A field system, cultivation and enclosure (NPRNs 411898, 411899 & 411900) that surrounds it may well be associated with the vaccary, but could equally relate to a later period of exploitation, when the seasonal occupation of the moorland became more permanent as represented by the 19th century farm of Hafotty Sion Llwyd (NPRN 27278)

Louise Barker, RCAHMW, October 2010

Sources:
Lynch F, 1993 Excavations in the Brenig Valley. A Mesolithic and Bronze Age Landscape in North Wales. Cambrian Archaeological Association.