Kan-Etsu Tunnel
The 84th longest tunnel in the world
The Kan-Etsu Tunnel (Kan'etsu Tonneru) is a tunnel on the Kan-Etsu Expressway in Japan that runs through Mt. Tanigawa from Minakami, Gunma to Yuzawa, Niigata. The northern tube was opened in 1985 and the southern tube was opened in 1991. The older one is used as a tunnel towards Niigata and the newer is towards Gunma.
Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).