Clarksville is a city in and the county seat of Montgomery County, Tennessee, and the fifth-largest city in the state behind Memphis, Nashville, Knoxville, and Chattanooga, respectively. The city had a population of 132,957 at the 2010 census, and an estimated population of 142,519 in 2012. Wikipedia

Mesa is a city in Maricopa County, in the State of Arizona and is a suburb located about 20 miles east of Phoenix. Mesa is the central city of the East Valley section of the Phoenix Metropolitan Area. Wikipedia