Bihoro Pass

Bihoro Pass offers one of the clearest views of Lake Kussharo, which at 79.3 square kilometers is Japan's largest caldera lake. The lake fills most of the vast Kussharo Caldera, a depression formed over 300,000 years ago. From the pass you can see the full arc of the shoreline, the post-caldera lava dome island at the center, and the Atosanupuri volcanic peaks to the east. The Mashu Kussharo Trail begins here, running 61 kilometers to the rim of Mashu Caldera. Ainu used this mountain route for centuries before a road was completed over the pass in 1920 after severe flooding isolated the region.