is in the U.S. state of Ohio and is the county seat of Delaware County. The municipality is located near the center of the state of Ohio, about 20 miles (32 km) north of Columbus, Ohio. Delaware was founded in 1808, incorporated in 1816. It is part of the Columbus Metropolitan Area. The population was 25,246 at the 2000 census. According to the US Census 2007 estimate, Delaware has a population of 32,986, while the Columbus-Marion-Chillicothe, OH Combined Statistical Area has 1,982,252 people. According to a list compiled by American Demographics Incorporated, Delaware County ranks fourteenth out of twenty areas in the United States designated as the fastest-growing in the year 2000.
The town is located about 24 miles north of Ohio's capital city, Columbus, due north along U.S. Highway 23.
According to the United States Census Bureau, the city has a total area of 15.1 square miles (39.1 km²), of which, 15.0 square miles (38.8 km²) of it is land and 0.1 square miles (0.3 km²) of it (0.66%) is water.