Pen yr Ole Wen is the seventh highest mountain in Snowdonia and in Wales.

The mountain lies to the north of Idwal Cottage youth hostel on the A5 road, from where it has a pyramidal appearance.

A slightly easier ascent involves starting from Tal-y-Llyn Ogwen, about a mile north-east from the hostel, following the stream until nearing the outflow from the mountain lake Ffynnon Lloer and then branching left to take the path up the ridge.

However, in 2004 Professor Hywel Wyn Owen at the Place-Name Research Centre at Bangor University in Bangor, Gwynedd resolved the matter saying that Ole comes from Goleddf, which means slope or hillside,[1] making the correct English translation: "Head of the White Slope".

Pen yr Ole Wen is often climbed as part of a longer route on the Carneddau range.