Memphis, Nashville, Knoxville, and Chattanooga are the focal points for rail, highway, water, and air transportation. All are located on important rivers and interstate highways, and all have airports served by the major airlines.
Railroad building began in Tennessee as early as the 1820s. During the 1850s, the basis for 20th-century rail transportation was laid: the Louisville and Nashville Railroad linked Tennessee to the northern states, and the Memphis and Charleston line established ties with the East Coast. In 2000, Tennessee had 2,929 rail mi (4,713 km) of track, of which 2,331 mi (3,751 km) were Class I track. No east-west passenger trains operate in the state today (Amtrak serves Memphis on the Chicago–New Orleans route), but considerable freight is hauled.
The first roads—such as the Natchez Trace, which connected Nashville with the southwestern part of the state—often followed Indian trails. Many roads in the early 1800s were constructed by private individuals or chartered turnpike companies. The introduction of the automobile shortly after the beginning of the 20th century brought the development of modern roads and highways. After 1916, the federal government began to share the high cost of highway construction, and the 1920s were a decade of extensive road building.
In 2000, Tennessee had 69,679 mi (112,137 km) of rural roads and 17,740 mi (28,549 km) of urban roads. The major interstate highway is I-40, crossing east-west from Knoxville to Nashville and Memphis. In 2000, 4,890,883 motor vehicles were registered in the state, and 4,251,228 Tennesseans held drivers' licenses.
The principal means of transportation during Tennessee's early history was water, and all the early settlements were built on or near streams. The introduction of steamboats on the Cumberland River in the early 19th century helped make Nashville the state's largest city and its foremost trading center. By mid-century, however, Memphis, on the Mississippi River, had surpassed Nashville in population and trade, largely because of cotton. Tennessee has about 1,000 mi (1,600 km) of navigable waterways. The completion in 1985 of the 234-mi (377-km) Tennessee-Tombigbee Waterway gave Tennessee shippers a direct north-south route for all vessels between the Tennessee River and the Gulf of Mexico via the Black Warrior River in Alabama. Although none of the waterway runs through Tennessee, the northern terminus is on the Tennessee River near the common borders of Tennessee, Alabama, and Mississippi. In 2000, the ports of Memphis and Nashville handled 18.3 million and 4.5 million tons of freight, respectively.
In 2002, there were 185 public and private airports, 87 heliports, 8 stolports, and 2 seaplane bases in the state. As of 2000, Memphis International Airport was among the world's busiest cargo-handling facilities; it was also the state's major air terminal in terms of enplanement. Nashville International retains the lead in terms of aircraft operations.