Iron age defended enclosure and field system. Site description from Coflein:
“A univallate, sub-oval enclosure, set on the summit of a mountain spur. It is subdivided by a scarp and ditch with a central entrance. There are remains of subsidiary enclosures, fields or paddocks, to the south-west, covering an area of about100m by 80m. An embanked trackway leads away to the north-west.”
coflein.gov.uk/en/site/92038/details/TWYN-Y-GAER%2C+SETTLEMENT%2C+TRALLWNG/