The Onuma surrounding area, from Meiji 36 (1903), as a Hokkaido prefectural park, nature has been protected and park facilities have been maintained, and it is one of the oldest nature parks even nationwide. In Taisho 4 (1915), on April 17, together with Miho no Matsubara (Shizuoka Prefecture) and Yabakei (Oita Prefecture), it was selected as one of Japan's New Three Views, and in Showa 32 (1957), receiving support from various quarters for a promotion movement saying "Onuma to Quasi-National Park," a request document was submitted to the prefecture. In July of the following 33rd year (1958), Onuma Prefectural Park received designation as the 13th Quasi-National Park, and Onuma and Mount Komagatake became a national special protection area.

In the three lakes including Lake Onuma, as many as 126 large and small islands float, adding delicate colors to the scenery of Onuma. Some of these islands are connected by arch-shaped bridges, and you can enjoy island hopping by walking from the park plaza. On the lake surface that has become a cove surrounded by islands, you should be able to find aquatic plants such as water lilies, and the figures of carp and crucian carp leaping up while swaying their leaves. If you are lucky, you may also be able to see kingfishers flying around the water surface, and squirrels busily gnawing on nuts.

As for autumn in Onuma Quasi-National Park, the entire lakeside area of Lake Onuma, Lake Konuma, Junsai Marsh, etc., vividly changes color. The lake colored with vivid crimson and Mount Komagatake boasting a clear ridge line vividly show us the beauty of nature. Cycling on the circuit road, going out onto the lake by canoe or boat, climbing Mount Higurashi (elevation 303m) which is located to the west of the park and from which you can view the entire lakeside area, etc., the methods for viewing autumn leaves are various. You can enjoy superb views with different aspects for each.

During winter, smelt fishing can be done. During December before the lake freezes, from the pier, and from early January to mid-March, on the ice. Because there are many facilities where you can go empty-handed and enjoy, by all means, challenge it. * As for the caught smelt, depending on the facility, they correspond to karaage for a separate fee.