Arakawa river is one of the rivers in Tokyo, which is 173 km long, 15th longest river in Japan and second longest in Kanto region, where Tokyo is located.
Arakawa means "Rough river" in Japanese and had long history of floods. The source of the river is in north west Saitama prefecture, Mt.Kobushi in Chichibu city.
One of the branches is the famous Sumida river which runs near Asakusa district but Sumida river was originally called Arakawa until 1965. Sumida river separates from Arakawa at Iwabuchi water gate which was built in 1924 and Arakawa canal was completed in 1930. Arakawa canal eventually became the main stream of Arakawa river and original stream was changed to Sumida river.
Arakawa is the widest river is Japan, which maximum width of embankment is 2537 m. Arakawa is one of the few rivers which still freight ships are in operation.