Clyde, the most important river of Scotland, rises in the southern part of Lanarkshire, out of the northern declivities of the chain of hills which may be regarded as a part of the Cheviots, dividing Lanarkshire, Peeblesshire, Selkirkshire, and Roxburghshire from Dumfriesshire. It runs principally in a N. W. direction, passing by Lanark, Hamilton, Bothwell, Rutherglen, Glasgow (which is the head of ship navigation), and Renfrew, and falls into the great estuary known as the frith of Clyde, formed by the concurrence of its own waters with those of Loch Long, coming down from the northward. This large river mouth, or arm of the sea, extends southward between the isles of Bute and Arran, which divide it on the west from Loch Fyne and Kilbrennan sound, and the shores of Renfrewshire and Ayrshire; off the latter it enters the Irish sea, between the mull of Cantyre and Kirkcolm point in Wigtonshire, nearly opposite Tor point, the extreme N. E. promontory of Ireland. The total length of the Clyde, from its source to the S. point of Bute island, is about 115 m.

Its valley is one of the most interesting and the richest in old historic and legendary lore, as well as in agricultural and commercial wealth, of all the beautiful vales of Scotland. Its magnificent falls of Corra Linn and Stone-byres have been described by the most eloquent writers, and its banks are the scene of Scott's "Old Mortality." The valley of the Clyde is famous for a peculiar race of strong black cart horses, known as the Clydesdale breed. Commercially, the embouchure of the Clyde monopolizes the American, West Indian, and South American trade, besides attracting to itself a large portion of the Indian and Australian commerce. This is the more remarkable, since the Clyde is for the most part, as a navigable river, an artificial stream. Formerly a shallow, rapid river, obstructed by sand banks, it has been converted into a line, uninterrupted, easily navigated avenue for ships of large burden, up to the splendid wharves of the great city which has grown up on its banks. The Forth and Clyde canal, which enters the latter river a little way below Kilpatrick, some 10 m. lower down the river than Glasgow, connects it with Bor-rowstounness on the Forth, about 30 m. above Leith, and affords a perfect communication between the E. and W. coasts.

It was commenced in 1777, and completed in 1790. Its total length is 35 m.; its greatest elevation, at its summit level, is 156 ft., which it reaches in 10 1/2 m. by means of 20 locks, while on its descent to the western tide water, which it reaches at Bowling bay, it has 19 locks. When full, it can carry vessels drawing 8 ft. of water, and its locks have a length of 74 ft. and a width of 20. It was the earliest considerable Scottish work of the kind, and continues to be one of the most important, being the great connecting channel for the trade of the E. and W. coasts of the kingdom. There is also a branch to this canal, 2 1/4 m. in length, terminating directly in Glasgow.