Pen y Garn is a Hewitt of 611 m in Cardiganshire [Ceredigion]. It clears the 2,000 ft line (609.6 m) by only 1.4 m.
Its closest neighbour in this register, Pumlumon Fawr, is 9.8 km away. All four of its nearest neighbours are higher, up to Pumlumon Fawr at 752.8 m. It sits below Pumlumon Fawr, only 9.8 km to the north and 141.8 m higher. It is one of only two register hills in the South-West Wales region, with Drygarn Fawr. It shares its height of 611 m with Creag Dhubh Mhor and Foel Goch. On the Hewitts height ladder it sits between Slieve Snaght (Donegal, C424390) (614.6 m) and Foel Goch (611 m). Its nearest higher summit, Y Garn (684 m, 8.3 km north), is a listed top not profiled here. The highest point is recorded as no feature: ground by gate, not a cairn. It falls on two OS 1:50,000 sheets, 135 and 147.
