Columbus is the capital and most populous city of the U.S. state of Ohio. With a 2020 census population of 905,748, it is the 14th-most populous city in the U.S., the second-most populous city in the Midwest after Chicago, and the third-most populous U.S. state capital after Phoenix, Arizona and Austin, Texas. Columbus is the seat of government of Franklin County; it also extends into Delaware and Fairfield counties. It is the core city of the Columbus metropolitan area, which encompasses ten counties in central Ohio. It had a population of 2,138,926 in 2020, making it the largest metropolitan area entirely in Ohio and 32nd-largest metro area in the U.S.

Ohio is a state in the Midwestern region of the United States. Ohio borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the west, and Michigan to the northwest. Of the 50 U.S. states, it is the 34th-largest by area. With a population of nearly 11.8 million, Ohio is the seventh-most populous and tenth-most densely populated state. Its capital and most populous city is Columbus, with other large population centers including Cleveland, Cincinnati, Dayton, Akron, and Toledo. Ohio is nicknamed the "Buckeye State" after its Ohio buckeye trees, and Ohioans are also known as "Buckeyes". Its flag is the only non-rectangular flag of all U.S. states.