The city of Clarksville is the county seat of Montgomery County, Tennessee, and the fifth-largest city in the state behind Memphis, Nashville, Knoxville, and Chattanooga. The city had a population of 132,957 at the 2010 census, and an estimated population of 149,176 in 2015. It is the principal central city of the Clarksville, TN-KY metropolitan statistical area, which consists of Montgomery and Stewart Counties in Tennessee, and Christian and Trigg Counties in Kentucky.