The Tennessee River is a 652-mile-long (1,049 km) river located in the southeastern United States. Flowing through the Tennessee Valley in the states of Tennessee, Alabama, Mississippi, and 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 (105,870 km2). It is also the lowest major tributary of the Ohio River, its mouth just 75 km (46.6 mi) upstream from the Ohio's confluence with the Mississippi River.