The Kingsway Tunnel is a toll road tunnel under the River Mersey between Liverpool and Wallasey. The 1.5 mi (2.4 km) tunnel carries the A59. It was built because the Queensway Tunnel – which was built in the 1930s to carry vehicles between Birkenhead and Liverpool – was unable to cope with the rise in postwar traffic.

A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is enclosed except for the portals, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods.