Tweed, river, in the SE. of Scotland, and partly in the N. of England; rises in a spring called Tweed's Well, in the extreme S. of Peeblesshire, near the sources of the Clyde and the Annan, and flows NE. through Peeblesshire, E. through Selkirkshire and Roxburghshire, and NE. between Berwickshire and Northumberland, to the North Sea at Berwick-upon-Tweed; length, 97 miles, 16 of which form the boundary between Scotland and England, the remaining 2 being entirely in Northumberland; area of basin, 1870 square miles, a drainage basin surpassed in Scotland only by that of the Tay; is celebrated for the varied scenery along its course, and has valuable salmon fisheries. Its chief tributaries are the Ettrick Water (which receives Yarrow Water), the Teviot, and the Till on the right bank; and Lyne Water, Gala Water, Leader Water, Eden Water, and the Whiteadder on the left bank.

(John Bartholomew, Gazetteer of the British Isles (1887))