Columbus is the state capital and the most populous city in Ohio. It is the 14th-most populous city in the United States, with a population of 860,090 as of 2016 estimates. This makes Columbus the 3rd-most populous state capital in the United States after Phoenix, Arizona and Austin, Texas, and the second-most populous city in the Midwestern United States, after Chicago. It is the core city of the Columbus, Ohio, Metropolitan Statistical Area, which encompasses ten counties. With a population of 2,021,632, it is Ohio's third-largest metropolitan area.Columbus is the county seat of Franklin County. The city proper has also expanded and annexed portions of adjoining Delaware County and Fairfield County. Named for explorer Christopher Columbus, the city was founded in 1812 at the confluence of the Scioto and Olentangy rivers, and assumed the functions of state capital in 1816.