Dinas-y-Prif is a rectangular enclosure, on ground sloping gently to the NW, surrounded by a single bank with external ditch. The enclosure measures 168ft from NE to SW by 156ft. The bank and the ditch have a total width varying from 35 to 48ft, with the bank rising some 5ft above the interior and some 10ft above the bottom of the ditch. At each corner the bank rises to form a circular mound some 4ft above the level of the top of the rampart.
Source: National Archaeological Record card SH45NE/1 RCAHMW 18.01.2008