Located in the premise of the shrine on the top of Mt. Haguro, the Dewa Sanzan Museum of History stores and exhibits a collection of materials telling us the history and the culture of the Three Mountains of Dewa. Among the many items displayed in the museum are many important cultural properties, including 190 bronze mirrors excavated from the Kagami-ike pond and bronze lantern posts, along with other items well representing the sacred place of the Shugendo, including magnificent Buddha statues created during the period when kami and Buddha were amalgamated, and the prestigious swords “Gassan” from the Nanboku-cho period.