|Length||225.0 km (139.8 mi)|
|South end||National Route 1 / National Route 4 / National Route 6 / National Route 14 / National Route 15 / National Route 17 in Nihonbashi, Chūō|
|North end||National Route 19 / National Route 153 in Shiojiri, Nagano|
|National highways of Japan|
Expressways of Japan
National Route 20 (国道20号, Kokudō nijū-gō) is a national highway connecting Tokyo and Shiojiri, Nagano prefecture in Japan. Originating at Nihonbashi in Chūō, Tokyo, it passes through Shinjuku and four other wards, and then seven cities, including Hachiōji in Tokyo. It follows a westward route into Kanagawa Prefecture, passing through the city of Sagamihara and one town. Continuing into Yamanashi Prefecture, the highway passes through nine cities and towns, among them the prefectural capital of Kofu. In Nagano Prefecture, National Route 20 passes through five cities and towns before entering Shiojiri, where it terminates at the intersection of National Routes 19 and 153. The highway is 225.0 km long.
National Route 20 is the successor to the Kōshū Kaidō, an Edo period highway connecting the shogunal capital of Edo and Kofu, then the principal city in Kai Province (or Kōshū, as it was also known). Parts of it still bear the old name.
- 4 December 1952 - First Class National Highway 20 (from Tokyo to Shiojiri, Nagano)
- 1 April 1965 - General National Highway 20 (from Tokyo to Shiojiri, Nagano)
- From Nihonbashi to Chiyoda (Sakuradamon intersection): Route 1
- In Hachioji, from Yokamachi intersection to Hachimancho intersection: Route 16
- In Otsuki, from intersection to Otsuki-bashi east intersection: Route 139
- From Kai (Ryuo-rittai intersection) to Nirasaki (Funayama-bashi kita intersection): Route 52
- Kanagawa Prefecture
- Yamanashi Prefecture
- Nagano Prefecture
- "一般国道の路線別、都道府県別道路現況" [Road statistics by General National Highway route and prefecture] (PDF) (in Japanese). Ministry of Land, Infrastructure, Transport and Tourism. Retrieved 19 February 2020.
- 一般国道２０号 (in Japanese). Ministry of Land, Infrastructure, Transport and Tourism. Kanto Regional Development Bureau. Archived from the original on 19 December 2010. Retrieved 29 November 2010.
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