Columbus is the capital and largest city of the U.S. state of Ohio. It is the 15th-largest city in the United States, with a population of 850,106 as of 2015 estimates. This makes Columbus the fourth-most populous state capital in the United States, and the third-largest city in the Midwestern United States, after Chicago & Indianapolis. It is the core city of the Columbus, Ohio, Metropolitan Statistical Area, which encompasses ten counties.