Columbus, Ohio is 2 times 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: 694 km2 calculated
Columbus is the capital of and the largest city in the U.S. state of Ohio. It is the 15th largest city in the United States with a population of 822,553. It is the core city of the Columbus, OH Metropolitan Statistical Area, which encompasses a ten county area. Wikipedia