Hamilton County, Ohio

Hamilton County is located in the southwestern corner of the U.S. state of Ohio. As of the 2020 census, the population was 830,639, making it the third-most populous county in Ohio. The county seat and most populous city is Cincinnati. The county is named for the first Secretary of the Treasury, Alexander Hamilton. Hamilton County is part of the Cincinnati–Middletown, OH–KY–IN Metropolitan Statistical Area.