Plas-y-gors Roman marching camp is laid out across east-facing slopes and covers an area of 8.47ha. Such camps were built by the army to protect their encampment and were sometimes occupied only for a single night. The camp was discovered from the air and was subsequently trenched; analysis of a pollen sample from beneath a rampart indicated some tree-clearance prior to construction. The site is now obscured by forestry. A Roman road passes close by, if not through, the camp (see nprn 407122), however, its precise route in this area is not known and it cannot be assumed that the present track follows its line.
Sources: St Joseph in the Journal of Roman Studies 48 (1958), 86-101
Crampton & Webley in the Bulletin of the Board of Celtic Studies 20.4 (1964), 440-446
Jones in the Bulletin of the Board of Celtic Studies 21.2 (1966), 174-8
RCAHMW Brecknock Inventory: Prehistoric & Roman (1986), 153-4
John Wiles, RCAHMW, 05.12.2007.