The Tennessee Valley begins in the upper head water portions of the Holston River, Watauga River, and Doe River in Northeast Tennessee and Southwest Virginia. It travels southwest into North Alabama. The roughly 150 mile (240 km) stretch within Tennessee is bound on the east by the Appalachian Mountains (including the Great Smoky Mountains) and on the west by the Cumberland Plateau and Cumberland Mountains. Near Chattanooga, Tennessee, the Tennessee River cuts though the Cumberland Plateau creating a canyon called the Tennessee River Gorge before it enters northern Alabama. The 100 mile (160 km) Alabama stretch of the valley runs mainly west before turning back north and re-entering Tennessee. In Alabama, the valley is bound on the north by the southern end of the Cumberland Plateau. On the south it is bound by the southern end of the Appalachians.
The valley continues back north into Tennessee, creating the dividing line between Middle Tennessee and West Tennessee, eventually reaching to the Ohio River in Western Kentucky, where it divides the region known as the Jackson Purchase from the rest of the state.
Geologically, the eastern Tennessee Valley consists of many small valleys and ridges within a great valley. The region is termed the Ridge and Valley Province and the great valley is termed the Great Appalachian Valley.
Knoxville, Tennessee, the most populous metropolitan area in the valley, is where the Tennessee River begins at the confluence of the Holston and the French Broad Rivers. Knoxville along with nearby Oak Ridge and Maryville-Alcoa, form a major research and manufacturing corridor anchored by the University of Tennessee, the Oak Ridge National Laboratory, and the Tennessee Valley Authority headquarters.
Chattanooga, Tennessee, is nicknamed "The Scenic City" for its vistas of the Tennessee Valley from atop the many mountaintops that surround the city. Chattanooga and its suburbs form the second most populous metropolitan area in the valley. The Battle of Chattanooga was fought on nearby Lookout Mountain.
Elizabethton, Tennessee, is a small city formerly known by the moniker "The City of Power" prior to the post World War II era of nuclear power production. It is located at the confluence of the Doe River and Watauga River downstream from the Watauga Reservoir and the Wilbur Reservoir. Both are maintained by the Tennessee Valley Authority.
Decatur, Alabama, known as "The River City", dominated the economic landscape of north Alabama until the late 1950s, when the space race catapulted its neighbor Huntsville (see below) into that position. For most of the 20th century up to that point, Decatur held the top position in terms of economic impact and population. Its mixture of river transport and rail access has made it a busy hub of business, commerce, and manufacturing (chemicals and textiles especially) flowing down the river on the barges and boats of numerous companies and docking at the Port of Decatur.
The City of Decatur also claims the nickname "The Heart of the Valley" because of its location near the exact center of the length of the Tennessee River. Also because most north/south shipping traffic is funneled through the town utilizing three river crossings that are main routes for rail and road traffic between Birmingham, and Nashville. The city is also an important river port that uses intramodal facilities to switch shipping methods between trains, trucks, and barges.
Huntsville, Alabama, "the Rocket City", has risen to be the center of north Alabama economic activity since the dawn of the space age in the 1950s. Its aerospace and military technology centers of Redstone Arsenal, Cummings Research Park, and NASA's Marshall Space Flight Center define the high-tech landscape for the state of Alabama.
Scottsboro, Alabama, "the Friendly City", is located on Highway 72, 40 miles east of Huntsville. It was founded in the mid 1850s and is most famous for the Scottsboro Boys and Unclaimed Baggage Center, as well as "First Monday," an open-air marketplace held in and around downtown on Mondays following the first weekend of a month.
Interstate 24 (abbreviated I-24, in keeping with other roads in the Interstate Highway System) connects Paducah, Kentucky, at the mouth of the Tennessee, with Chattanooga via Clarksville and Nashville. Much of this road's route in Kentucky and Tennessee actually lies outside the Tennessee Valley.
Interstate 40 runs east-west across the Tennessee portion of the Tennessee Valley. Connecting Nashville with Knoxville and Asheville, North Carolina.
Interstate 65 is the main north-south road in the central part of the valley, connecting Birmingham, Huntsville-Decatur, and Nashville.
Interstate 565/Alabama 20/Alt 72 is the main corrider of the Huntsville-Decatur Combined Statistical Area that links the Huntsville Metropolitan Area and the Decatur Metropolitan Area, along with all of the scientific research and space exploration institutions in Northern Alabama. The road also provides a vital link to I-65 for both urban areas.