The Three Mountains of Dewa refer to the three sacred mountains of Mount Haguro, Mount Gassan and Mount Yudono, which are clustered together in the ancient province of Dewa. Holy to the Japanese Shinto religion and especially the mountain ascetic cult of Shugendo, Dewa Sanzan are a popular pilgrimage site visited by many, including famed haiku poet Matsuo Bashō.
The Haguro Five-story Pagoda is a recognised national treasure of Japan.