Japan · JP

Iwaonai Lake

Iwaonai Lake is a vast reservoir on the Teshio River — Japan's northernmost great river — nestled in the birch-forested hills of Shibetsu City in northern Hokkaido. Its most iconic sight is the Iwaonai Ohashi Bridge arcing gracefully across the mirror-still water, a striking dialogue between engineered form and untouched wilderness. Created in 1971 by the completion of Iwaonai Dam, the lake holds over 107 million cubic metres of water, making it the ninth-largest artificial lake in Hokkaido. Surrounding it, a mix of paper birch, Mongolian oak, and Ezomatsu fir forests shelters a surprising diversity of wildlife, including fish species listed in Japan's Red Data Book. Anglers come for char, trout, and smelt; paddlers enjoy the calm open water; and campers find a peaceful base at the adjacent Shirakaba (Birch) Campground.