Located at an elevation of 130m, the lake has a circumference of about 800m and a depth of about 2m. To encourage freshwater fishing, a dike was constructed in 1917. Rishiri, three small marshes were combined into one and named "Hime-numa" (Princess Swamp) after the trout that were released into it. The store (rest house) sells pictures and postcards of Rishiri and Hime-numa scenery, flowers, birds, etc., and coffee made from Mt. There are no restrooms along the Hime-numa lakeside, so use the restrooms in the parking lot beforehand!