National Route 406 is a national highway of Japan connecting Ōmachi, Nagano and Takasaki, Gunma in Japan, with a total length of 192.5 km (119.61 mi).

References

  1. ^ "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 12 February 2020.