The Tennessee River is a 652 mi long river located in the southeastern United States in the Tennessee Valley. Flowing through the states of Tennessee, Alabama, Mississippi, Kentucky, it begins at the confluence of French Broad and Holston rivers at Knoxville, and drains into the Ohio River near Paducah, Kentucky. It is the largest tributary of the Ohio, …The Tennessee River is a 652 mi long river located in the southeastern United States in the Tennessee Valley. Flowing through the states of Tennessee, Alabama, Mississippi, Kentucky, it begins at the confluence of French Broad and Holston rivers at Knoxville, and drains into the Ohio River near Paducah, Kentucky. It is the largest tributary of the Ohio, and drains a basin of 40,876 sq mi.