Tyne (tĪn) [key], river, c.62 mi (100 km) long, NE England, formed near Hexham, Northumberland, by the confluence of the North Tyne (33 mi/53 km long; rising in SW Cheviot Hills) and the South Tyne (32 mi/52 km long; rising in the N Pennines). The Tyne flows eastward through the Tyneside conurbation to the North Sea below Newcastle upon Tyne. The lower Tyne is lined with docks, shipbuilding yards, a variety of industrial plants, and coal-mining and ironworking towns. The Tyne was made navigable to Newcastle upon Tyne, its chief port, at the turn of the 20th cent. South Shields, Gateshead, Jarrow, and Wallsend are important ports on the river. Three bridges cross the Tyne at Newcastle upon Tyne; the Tyne Tunnel (opened 1967) connects Jarrow and Willington.