is a tunnel on National Sengan Road #46 in northern Japan that runs between Iwate prefecture and Akita prefecture borders with approximate length of 2.544 km. It was completed and opened in 1975.
See also List of tunnels in Japan Seikan Tunnel Tappi Shakō Line Sakhalin–Hokkaido Tunnel Bohai Strait tunnel
References
External links Gov. maps.gsi.go.jp Sengan Tunnel Sengan tunnel inspection