Columbus, Ohio is 2.1 times larger than Knoxville, Tennessee.
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
Area: 332 km2 calculated
Knoxville is a city in the U.S. state of Tennessee, and the county seat of Knox County. The city had a population of 178,874 as of the 2010 census and an estimated population of 183,270 in 2013, making it the state's third largest city. Wikipedia