Pen-y-Gaer, Llanidloes, is a stone-walled, ditchless summit-top oval enclosure, measuring 68m by 44m. The ground falls away steeply to the east and west, and on the gentler north and south approaches are additional walls c.55m and 18m from the enclosure respectively. There is a well preserved oblique entrance passage through the south-east enclosure wall, without which are two, possibly natural, monoliths. A modern cairn lies within the enclosure.

(source Os495card; SN98NW5)
RCAHMW AP945030/45-6; 955037/66
J.Wiles 13.01.04

Field visit by T. Driver, RCAHMW, 5th October 2005. Site survives well. Organised clearance/excavation of tumbled scree fronting the western rampart has taken place at some point, revealing the lower courses of the preserved rampart wall for a short distance. In the rampart screes of the southern rampart, near the gateway, two or three lines of potential wall faces are visible within the rubble core. The interior is uneven and rocky but at least two level areas with rock-cut rear 'walls' can be made out, forming shallow platforms. There are also boggy areas, and a wide level area inside the south gateway, potentially representing a 'yard' immediately inside the main gate.

T. Driver. 2005.10.10.