Circleville is a city in and the county seat of Pickaway County, Ohio, United States. The city is situated along the Scioto River, 25 miles south of …Circleville is a city in and the county seat of Pickaway County, Ohio, United States. The city is situated along the Scioto River, 25 miles south of Columbus. The population was recorded to be 13,927 in the 2020 census.