CUMBERLAND RIVER, a large southern branch of the Ohio river, U.S.A., rising in the highest part of the Cumberland plateau in south-east Kentucky, and emptying into the Ohio in Kentucky (near Smithland) after a devious course of 688m. through that State and Tennessee. It drains a basin of somewhat more than 18,000 sq. miles. At the Great Falls, in Whitley county, (Ky.), it drops precipitously 63 feet. Above the falls it is a moun tain stream, of little volume in the dry months. It descends rap idly at its head to the highland bench below the mountains and tra verses this to the falls, then flows in rapids (the Great Shoals) for about 1 om. through a fine gorge with cliffs 300-400f t. high and descends between bluffs of decreasing height and beauty into its lower level. Save in the mountains its gradient is slight, and below the falls, except for a number of small rapids, the flow of the stream is equable. Timbered ravines lend charm to much of its shores, and in the mountains the scenery is most beautiful.
Below Nashville the stream is about 400 to 5oof t. wide, and its high banks are for the most part of alluvium, with rocky bluffs at intervals. At the mouth of the river lies Cumberland island, in the Ohio. During low water of the Ohio the Cumberland discharges around both ends of the island, but in high water of the Ohio the gradient of the Cumberland is so slight that its waters are held back, forming a deep quiet pool that extends about 2om. up the river. Commerce on the Cumberland was once of great impor tance, it being navigable for light-draught boats through about 5oom. under favourable conditions—Burnside, Pulaski county, 518m. from the mouth, being the head of navigation. A system of locks and dams below Nashville was planned in 1846 by a private company, which accomplished practically nothing. Since 1832 the Federal Government has expended over $6,000,000 on canalization and open channel projects. During the Civil War, Fort Donelson on the Cumberland, and Fort Henry near by on the Tennessee were erected by the Confederates, and their capture by Flag-officer A. H. Foote and Gen. Grant (Feb. 1862) was one of the decisive events of the war.