Chattanooga, Tennessee is 65% larger than Clarksville, Tennessee.
Area: 390 km2 calculated
Chattanooga is the fourth-largest city in the U.S. state of Tennessee, with a population of 167,674 as of the 2010 census, and an estimated population of 171,279 in 2012. It is the seat of Hamilton County. Wikipedia
Area: 236 km2 calculated
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