Cincinnati is a city in Hamilton County, Ohio, United States, and its county seat. Settled in 1788, the city is located on the northern side of the co…Cincinnati is a city in Hamilton County, Ohio, United States, and its county seat. Settled in 1788, the city is located on the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line with Kentucky. It is the third-most populous city in Ohio and 66th-most populous in the U.S., with a population of 309,317 at the 2020 census. The city is the economic and cultural hub of the Cincinnati metropolitan area, Ohio's most populous metro area and the nation's 30th-largest, with over 2.3 million residents.