Pen uchar'r llan earthwork is an oval ringwork enclosure. The Scheduled Ancient Monument dominates the northern end of Llanfor. It has been identified as one of a pair of earthworks, the other being Tomen-y-castell (NPRN 406424), located some 1.25km to the north-east. A footpath is depicted on historic (1889) Ordnance Survey mapping, which would have connected Tomen-y-castell to the northern end of Llanfor, and may represent a historic route. Pen uchar'r llan has been identified as a possible medieval commotal structure. It is thought that Llanfor was once the commote centre of Penllyn, before it was superseded by Bala sometime before the thirteenth century. The customs and tolls of the market and fair of Llanfor were transfered to the new foundation of Bala in 1310-1311. The earthwork overlooks the church from an elevated position some 70m north. The two may have been contemporary and have formed elements of the same settlement. The earthwork is defined by a massive rampart, up to 5.2m high, with traces of an external ditch. The area enclosed measures some 26m by 18m. The enclosure has been mutilated on its south side.

Beverley Smith, J, Beverley Smith, Ll, 2001, History of Merioneth II, 39, 413
Ordnance Survey, 1889, first edition 25inch

N Vousden, 18 June 2012