Chattanooga, Tennessee is 13% larger than Atlanta.
Area: 346 km2 calculated
Atlanta is the capital of and the most populous city in the U.S. state of Georgia, with an estimated 2013 population of 447,841. Atlanta is the cultural and economic center of the Atlanta metropolitan area, home to 5,522,942 people and the ninth largest metropolitan area in the United States. Wikipedia
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