A unique array of archaeological features, first recognised as cropmarks, were excavated in advance of the construction of an industrial estate in 1966-7. The site lies on generally level ground between the rivers Cegin and Ogwen to the west of Llandegai village. Its features included several Neolithic ritual or ceremonial monuments, two henges - circular enclosures - and a cursus - a linear enclosure - apparently aligned on Llandegai church. There were also several ring-ditches marking the sites of Bronze Age round barrows. A later Prehistoric settlement was built within the larger henge. Centred on the largest roundhouse known in Wales, this settlement appears to have been occupied into the Roman period. In the early medieval period a small timber shrine or chapel was built over the cursus. This was the focus for a small inhumation cemetery.

A further cropmark complex has been recorded to the north-east (NPRN 404666). This includes a pair of early medieval type square ditched barrows. Excavations to the south have revealed evidence for Bronze Age land-use and a later-Prehistoric and Roman period settlement (NPRN 405440).

Source: Lynch & Musson in Archaeolgia Cambrensis 150 for 2001 (2004), 17-142

John Wiles, RCAHMW, 25 February 2008.