Delaware is a city in and the county seat of Delaware County, Ohio, United States. Delaware was founded in 1808 and was incorporated in 1816. It is located near the center of Ohio, is about north of Columbus, and is part of the Columbus, Ohio Metropolitan Area. The population was 34,753 at the 2010 census, while the Columbus-Marion-Chillicothe, OH Combined Statistical Area has 2,002,604 people.