Columbus (/ k ə ˈ l ʌ m b ə s /, kə-LUM-bəs) is the capital and most populous city of the U.S. state of Ohio.With a 2020 census population of 905,748, [10] 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 county seat of ...