Hidaka Sanmyaku-Erimo Quasi-national Park is a natural area consisting of three districts: 1) the rugged area of the Hidaka Mountains, known as the backbone of Hokkaido; 2) a stretch of coastal cliffs extending from Hiroo Town to Cape Erimo; and 3) the area of Mt. Apoi - a flower-covered peridotite mountain. With a total area of 103,447 hectares, it is Japan's largest park of its kind.
The quasi-national park area is classified into five zones based on the need for protection: a Special Protection Zone, three Special Zones (Classes I - III), and an ordinary area. Permission from the Governor of Hokkaido is needed for certain activities in the Special Protection Zone and the three Special Zones, such as constructing, extending or rebuilding structures, installing advertising displays and collecting rocks or alpine plants.