Tennessee (i /tɛn
ɪˈsiː/) is a U.S. state located in the Southeastern United States. It has a population of 6,214,888, making it the nation's 17th-largest state by population, and covers 42,169 square miles (109,220 km2), making it the 36th-largest by total land area. Tennessee is bordered by Kentucky and Virginia to the north, North Carolina to the east, Georgia, Alabama, and Mississippi to the south, and Arkansas and Missouri to the west. The Appalachian Mountains dominate the eastern part of the state, and the Mississippi River forms the state's western border. Tennessee's capital and second largest city is Nashville, which has a population of 626,144. Memphis is the state's largest city, with a population of 670,902. Nashville has the state's largest metropolitan area, at 1,521,437 people.
The State of Tennessee is rooted in the Watauga Association, a 1772 frontier pact generally regarded as the first constitutional government west of the Appalachians. What is now Tennessee was initially part of North Carolina, and later part of the Southwest Territory. Tennessee was admitted to the Union as the 16th state on June 1, 1796. In the early 19th-century, Tennessee was home to some of American history's most colorful political figures, among them Davy Crockett, Andrew Jackson, and Sam Houston. Tennessee was the last state to leave the Union and join the Confederacy at the outbreak of the U.S. Civil War in 1861, and the first state to be readmitted to the Union at the end of the war. Tennessee furnished more soldiers for the Confederate Army than any other state, and more soldiers for the Union Army than any other Southern state. Tennessee has seen some of the nation's worst racial strife, from the formation of the Ku Klux Klan in Pulaski in 1866 to the assassination of Martin Luther King in Memphis in 1968. In the 20th century, Tennessee transitioned from an agrarian economy to a more diversified economy, aided at times by federal entities such as the Tennessee Valley Authority. In the early 1940s, Oak Ridge, Tennessee was established to house the Manhattan Project's uranium enrichment facilities, helping to build the world's first atomic bomb.