Nyidên (Tibetan: ཉི་བརྟེན་, Wylie: nyi brten), or Yading (Chinese: 亚丁; pinyin: Yàdīng), is a national level reserve in Daocheng County, in the southwest of Sichuan Province, China. It is a mountain sanctuary and major Tibetan pilgrimage site comprising three peaks sanctified by the 5th Dalai Lama. The peaks are seen as emanations of the three boddhisatvas Chenrezig (Avalokiteśvara), Jampayang (Manjushri) and Chanadorje (Vajrapani), with Chenrezig being the highest peak at 6032 meters above sea level. It is served by Daocheng Yading Airport.