Dramatic Llyn Ogwen, one of the most popular lakes in Wales, is situated south of Bangor, and lies between the two mountain ranges of the Carneddau and the Glyderau. It stands at the head of the Nant Ffrancon Valley approx. four miles from the village of Bethesda. The lake is surrounded by high mountains, including Pen yr Ole Wen and Tryfan, considered to be one of the finest mountains in Wales. Ogwen is an extremely shallow lake, with a depth of only three metres, and is around a mile long. It lies at a height of 310 metres above sea level. The lake is the source of the River Ogwen.