Llyn Crafnant is a lake that lies in a valley in North Wales where the northern edge of the Gwydir Forest meets the lower slopes of the Carneddau mountains and, more specifically, the ridge of Cefn Cyfarwydd. The head of the valley offers a profile of crags which are silhouetted at sunset. The Forest Park guide (2002) states that "the (view along Llyn Crafnant) is one of the most breathtaking views in all Snowdonia". The summits include Crimpiau 475 metres (1558 feet) and Craig Wen 548 metres (1798 feet), which provide views to Moel Siabod and the Ogwen Valley, and Snowdon. Further up is Creigiau Gleision. At 63 acres (250,000 m²) it is the best part of a mile long, although it was clearly once much longer - its southern end shows the evidence of centuries of silting.