is a highway on the island of Honshu in Japan. It originates at Nihonbashi in Chà «à Â, Tokyo, and terminates in the city of Niigata (the capital of Niigata Prefecture), where it meets National Routes 7, 8, 49, 113 and 116).
National Route 17 measures 350.3 km in length. It incorporates parts of two ancient highways, the Nakasendà  and Mikuni Kaidà Â. The newer Kan-Etsu Expressway parallels National Route 17.
In addition to Chà «à Â, National Route 17 passes through Itabashi. It links the prefectural capitals of Saitama (Saitama Prefecture) and Maebashi (Gunma Prefecture).