The Holston River is a major river system of southwestern Virginia and East Tennessee. The three major forks of the Holston (its North, Middle and South Forks) rise in southwestern Virginia and have their confluence near Kingsport, Tennessee. From there the river flows roughly southwestward, just north of Bays Mountain, until it reaches its confluence with the French Broad River just east of downtown Knoxville, Tennessee. This confluence is considered to be the headwaters of the Tennessee River.
The Holston River valley is greatly developed for electrical power generation, both with hydroelectric dams and coal-fired steam plants. In its upper reaches some of these plants are controlled by private interests; in the downstream portion they are owned by the United States Government's Tennessee Valley Authority. Among the dams and associated reservoirs on the South Fork Holston River are Boone Dam and Boone Reservoir; Fort Patrick Henry Dam and Fort Patrick Henry Reservoir, and South Holston Dam and South Holston Reservoir. Cherokee Dam on the Holston River forms Cherokee Reservoir.
Although the Holston River is now defined as ending at the French Broad River to form the Tennessee River at its mile post 652 in Knoxville, until 1933 the terminus of the Holston River was defined as the location 51 miles downstream of Knoxville at Lenoir City where the Little Tennessee River enters the river. That point, the confluence of the Holston and Little Tennessee Rivers, was considered to be the beginning of the Tennessee River, 601 miles upstream from the Ohio River at Paducah, Kentucky. According to Tennessee Valley Authority historians, when the Tennessee Valley Authority was created in 1933, Congress mandated that the TVA headquarters be located on the banks of the Tennessee River. Since the TVA headquarters were to be located in downtown Knoxville on what was then the Holston River, in order to fulfill the Congressional mandate the official start of the Tennessee River was moved upstream from Lenoir City to the confluence of the Holston and French Broad Rivers.