Lake Shumarinai was created as part of the construction of the Uryu Dam, and is the largest man-made lake in Japan, with a surface area roughly the size of 30 Tokyo Disneylands. The Lake Shumarinai area was designated a prefectural natural park in 1974 (Showa 49), and is home to a vast expanse of virgin land that is subject to strict conservation regulations, and still retains its original natural form.

The lake, with 13 islands of various sizes, changes its appearance with each season. The complex topography, reminiscent of a Nordic fjord, nurtures lake creatures and deep virgin forests, and the lake, surrounded by deep nature, is known as a mysterious lake, home to the Japanese Hucho, the largest freshwater fish in Japan. During trout season, anglers from within and outside Hokkaido, and sometimes even from overseas, visit the lake, and in winter, it becomes a lively place for smelt fishing.

During the summer camping season, many campers visit the area. As it is not a tourist destination, it is popular with experienced campers and riders, and one of its features is that it has many repeat visitors as a place where they can relax and spend their time.