Lake Towada (十和田湖, Towada-ko) is the largest crater lake in Honshū island, Japan. Located on the border between Aomori and Akita prefectures, it lies 400 meters (1,800 ft) above sea level and is 327 m (1,073 ft) deep, drained by the Oirase river. With a surface area of 61.1 km², Towada is Japan's 12th largest lake, its bright blue color is due to its great depth.