Lake Nakatsuna

Lake Nakatsuna
Lake Nakatsuna in winter
Lake Nakatsuna
LocationŌmachi, Nagano, Japan
Coordinates36°30′N 137°51′E / 36.500°N 137.850°E / 36.500; 137.850
Lake typeEutrophic lake
Surface area12.5 hectares (31 acres)
Max. depth12 metres (39 ft)
Surface elevation820 m (2,690 ft)
SettlementsNear Omachi, Nagano, Honshū, Japan

Lake Nakatsuna (中綱湖, Nakatsuna-ko) is a lake in Ōmachi Nagano Prefecture, Japan. It is one of the "Nishina Three Lakes" (Lake Aoki, Lake Nakatsuna and Lake Kizaki). Its sediments have been studied in an effort to better understand climate change in Japan, finding evidence of the Medieval Warm Period and Little Ice Age.