The Bryniau'r-Plas enclosure is a low circular and univallate earthwork approximately 100m in diameter. It is sited on the flat summit of a low hill to the south of the Nant-y-Garth pass in improved pasture. It was discovered during RCAHMW aerial reconnaissance on 17 March 2004.

T Driver, RCAHMW, 9 July 2004.