Pen Y Garn Castle

Pen y Garn castle is a fragmentary fortification built on the top of a rocky uotcrop crowning steep slopes above Traeth Mawr, the low-lying floodplain of the Afon Glaslyn. The strength of the site is easy to appreciate, although the nature of the ruin is difficult to follow. The site is on private land, and it is clearly signposted that visitors are not permitted.

The roughly flat summit has a great deal of bare rock, and there are walls across it which vary in height, width and orientation. However, that some of these are very thick – and presumably much older – than the others is immediately apparent, and it although they are mostly drystone, it is very likely that the older walls were originally clay bonded, as was common in lime-poor Wales. The area of the summit, which is roughly oval-shaped, measures perhaps 30 metres east-west and fifty north-south. The best preserved section of walling that is clearly of great age is along the northern part of the circuit, and it gets gradually less well-defined travelling clockwise along the eastern parts. The southern and western parts are all but non-existent, and it is here that the cliffs drop precipitously away. A sloping area to the north-west is shown on Ordnance Survey mapping as containing a number of small enclosures, but these are not obviously part of the fortification and are more likely to be more modern sheep pens to my mind. There is no obvious approach or break in the walls to indicate a gate opening, but it would not be unreasonable to suppose it was on the north-eastern side where a cleft in the rock would provide a natural defensive approach – unless a goat-path wound around the base of the walls!

The history of Pen y Garn is completely unknown, and it was not in fact identified until 1990 as being of archaeological interest. However it is generally considered to have been one of a small number of castles erected in Gwynedd following the death of Owain ap Gruffudd in 1170, and the subsequent power struggle between his sons. Each of these sites would therefore seem to have been erected in a position of geographical prominence, expressing the power and wealth of the respective prince. However, no archaeology has been done on any of the sites, so this is at present a widely accepted – but as yet unproven – theory. It is unlikely to have remained in use into the mid 13th century.

RCAHMW Coflein database entry