Clarksville is a city in and the county seat of Montgomery County, Tennessee, United States, and the fifth largest city in the state. The population was 132,929 in 2010 United States Census. Clarksville is the ninth fastest growing city in the nation and the principal central city of the Clarksville, TN-KY metropolitan statistical area, which consists of Montgomery County, Stewart County, Tennessee, Christian County, Kentucky, Trigg County, Kentucky and is the 10th fastest growing Metropolitan Statistical Area (MSA) in the nation.The city was incorporated in 1785, making it Tennessee's first incorporated city, and named for General George Rogers Clark, frontier fighter and Revolutionary War hero, brother of William Clark of the Lewis and Clark Expedition.Clarksville is one of the south's most historic cities and the home of Austin Peay State University; The Leaf-Chronicle, the oldest newspaper in Tennessee; and neighbor to the Fort Campbell, United States Army base. Fort Campbell is the home of the 101st Airborne Division (Air Assault), and is located approximately 10 miles (16 km) from downtown Clarksville, straddling the Tennessee-Kentucky state line. It is officially Fort Campbell, Kentucky due to the fact the base U.S. Post Office is on the Kentucky side of the base; the majority of Fort Campbell is within the state of Tennessee.