Ōnuma Quasi-National Park is a 90.83 km2 (35.07 sq mi) quasi-national park on the Oshima Peninsula in southwest Hokkaidō, Japan. The park encompasses the volcanic Hokkaidō Komagatake as well as the Ōnuma and Konuma ponds, which abut against the west slope of the mountain. The park, which was designated as quasi-national in 1958, is the smallest major park in Hokkaidō. Ōnuma and Konuma were created when mudflows due to eruptions of Hokkaidō Koma-ga-take dammed up depressions at the base of the mountain. The ponds, which are dotted with watershields, are surrounded by birch and maple forests.