Tennessee River, the largest tributary of the Ohio, formed by the union of the Clinch and Holston rivers, which rise in S. W. Virginia, and unite near Kingston, Roane co., Tenn. At first the course of the Tennessee is S. W. to Chattanooga, near the S. line of the state, where it passes through a part of the Cumberland range of mountains in a series of bends, and again turns S. W., entering the state of Alabama, and at Gunter's Landing, Marshall co., Ala., assumes a direction nearly W. by N. Between Lauderdale and Lawrence counties it spreads in a broad but shallow expansion called Muscle shoals, flowing over flint and limestone rocks in a succession of rapids for 36 m., and affording a large amount of water power. It afterward passes near Tuscumbia and Florence, on opposite sides, and at Chickasaw on the Mississippi line turns N. W., and forms the boundary thence to the Tennessee line between Alabama and Mississippi. Reentering Tennessee, after a circuit of nearly 300 m. in Alabama, it flows almost due N. till it reaches Birmingham, Ky., when it turns W. N. W. and enters the Ohio at Paducah, McCracken co., 50 m. from the mouth of the latter. Its length from Kingston to Paducah is estimated at 800 m., but from the source of its longest affluent, the Holston, it is more than 1,100 m.

Its principal tributaries are the Sequatchie, Paint Rock, Flint, and Duck rivers, and Elk and Shoal creeks, entering it from the right; and the Hiawassee, Big Sandy, and Clark's rivers, and Town and Big Bear creeks, from the left. The fall of the river in its whole course is computed at about 2,000 ft. It is navigable from the Muscle shoals to its entrance into the Ohio, 259 m.; and above the shoals steamboats ascend to Knoxville, nearly 500 m. The scenery on the upper portion of the river is very beautiful. Darby estimates the area drained by the Tennessee and its tributaries at 41,000 sq. m.