MERSEY, a river of England, is formed by the union of several small streams which take their rise in the hills near the borders of Yorkshire, Cheshire, and Derbyshire, where these three counties meet in a single point. The principal of these streams are the Tame and the Goyt; and from Stockport, where these two unite, the river thus formed takes the name of the Mersey, flows to the W., forming all along its course the boundary between Cheshire and Lancashire, and after a course from Stockport of 55 miles in length, falls into the Irish Sea below Liverpool. The principal tributaries of the Mersey are,—the Irwell, which flows past Manchester, and falls into the Mersey from the N., below the junction of which the river becomes navigable; and the Weaver, which joins it from the S. just before it expands into a large estuary. This estuary, which is 17 miles in length and 3 miles across at the broadest part, contracts at its mouth to a breadth of little more than three-quarters of a mile, so as to have the appearance, from several points of view, of a large inland lake. The country through which the Mersey flows is level; but in some parts the scenery is very picturesque. The principal towns and villages on its banks are,—Stretford, Warrington, Hale, Garston, and Liverpool, on the right bank; and Stockport, Runcorn, Ince, and Birkenhead, on the left.