Freshwater Lake in southwest Hokkaido, Japan, near Neipu Bay, part of Zhiyu Toya National Park, also known as Crater Lake. The lake is about 10 kilometers in diameter, nearly circular, with an area of 70.72 square kilometers, a circumference of 50 kilometers, the deepest 180.0 meters, the average water depth 117.0 meters, the water storage 8.19 cubic kilometers, and the lake is 84 meters above sea level. The northernmost limit of Japan's unfrozen lake is that there is a botanical garden on the middle island of the lake.