The River Tweed, or Tweed Water (Scottish) is a river 97 miles (156 km) long that flows east across the Border region in Scotland and northern England. Tweed cloth derives its name from its association with the river. The Tweed is one of the great salmon rivers of Europe and the only river in England where an Environment Agency rod licence is not required for angling. The river generates a large income for the local Borders region, attracting anglers from all around the world. It is one of the best salmon rivers in Scotland. Tweed is an Old Brythonic (Celtic) name meaning "border".
It flows primarily through the scenic Borders of Scotland, and eastwards from the settlements of Birgham and Carham forms the historic boundary between Scotland and England.
It rises in the Lowther Hills at Tweed's Well near to where the Clyde (draining northwest (10 kilometres (6.2 mi) from Tweed's Well), and the Annan (draining south (1.9 kilometres (1.2 mi) from Tweed's Well) also rise. "Annan, Tweed and Clyde rise oot the ae hillside" is a saying from the Borders. East of Kelso, it's lower reaches enter Northumberland in England where it joins the North Sea at Berwick-upon-Tweed.
The river's valley floor is a drumlin field. It is the relic of a paleo-ice stream that flowed through the area during the last ice age. Major towns through which the Tweed flows include Innerleithen, Peebles, Galashiels, Melrose, Kelso, Coldstream and Berwick-upon-Tweed, where it flows into the North Sea. Tweed tributaries include:
The upper parts of the Tweed catchment form the area known as Tweeddale, part of which is protected as the Upper Tweeddale National Scenic Area, one of 40 such areas in Scotland, which are areas of exceptional scenery and protected from inappropriate development.