Established as the county seat of Pickaway County in 1810, Circleville derives its name from the circular portion of the large Hopewell-era earthwork upon which it was built. The Circleville Earthworks was comprised of an 1,100-foot diameter circle connected to a 900-foot square. Town director Daniel Dreisbach integrated the plan into the prehistoric landscape by platting the town directly atop the earthworks. An octagonal courthouse stood directly in the center.
In just two decades, dissatisfaction arose with Circleville's unique radial-concentric street layout. In 1837 the Ohio General Assembly authorized The Circleville Squaring Company to convert the peculiar town plan into a conventional grid with rectangular blocks. Today, Circleville remains one of the earliest examples of urban redevelopment in the United States.