The Shizunai River running through Shin-Hidaka Town in the eastern part of Hokkaido is the representative river in the Hidaka area. Of the 683.4 square kilometer in watershed area and 69.9 kilometer in total length, about 70 % is the mountainous zone in the national forest, where bountiful nature remains intact. The river flows out of Mt. Petegari and Mt. Idonnappu in the Hidaka Mountain Range, where many cirques are found. Surrounded with sheer cliffs, the river has a lot of waterfalls.

In the old days, the Shizunai River was called the Shibechari River, the name of which derived from the Ainu word “shipe-ichan,” meaning “a spawning place of salmon.” The river is famous as the place where stream gold was panned in the Edo period (1603-1868). It is also known as the wintering place of swans. About 200 Whooper swans come to stay in winter, which is the largest in number among all the rivers in Hokkaido. Also, whistling swans, a very rare species of swan, can be seen in this river, although only a few can be confirmed all over the country in Japan, The Shizunai River was designated as a Wildlife Protection Area in 1965.