Shinano river信濃川alternative words: Shinanogawa river, Shinanogawa, Shinano-gawa, Shinano gawa keywords: nagano , river related topics: Nagano Prefecture , Niigata prefecture , Komoro city , Nagano city , Niigata city explanation: Taking its source in the south-eastern mountains of Nagano Prefecture and pouring into Japan Sea at Niigata city, it is the longest river in Japan (367 km long). Shinano river has 2 main branches: Chikuma river (the longest) which drains the east of Nagano Prefecture and Sai river which drains the west. Their confluent is near Nagano City in the north of prefecture. | |