Fujisawa, Kanagawa
The Sakai River has with the length of 52.1 km and the basin size of 210.7 square km. It starts from Aihara-machi (Japanese: ), Machida, Tokyo, to Katase, Fujisawa, Kanagawa, near Enoshima Island, It is called "Sakai", meaning "border", because it flows on the border of the former provinces of Musashi and Sagami.