[2][3] Mount Apoi is part of the Hidaka Mountains, a mountain range in southeastern Hokkaidō which was formed from a collision between two continental plates 13 million years ago.

Apoi offer a rare visible glimpse of the Earth's mantle, thrust up from the depths of the earth by global-scale dynamic ground movement.

Apoi provides habitats for alpine vegetation due to its unique soil, weather and geographical conditions.

It is home to Hidakaso (Callianthemum miyabeanum) and a host of other endemic species.

The area's alpine plant communities have been collectively designated as a Special Natural Monument of Japan.