The city's name is derived from its originally layout after 1810 within the 1,100 ft (340 m) diameter of a circle of a Hopewell tradition earthwork dating to the early centuries of the Common Era. The county courthouse was built in the center of the innermost circle. By the late 1830s residents had tired of this design and gained authorization from the state legislature to change the layout to a standard grid, which was accomplished by the mid-1850s. All traces of the Hopewell earthwork were destroyed here, although hundreds of other monuments may be found in the Ohio Valley.

By the mid-18th century, the Lenape (Delaware Indians) were pushed west from Pennsylvania by European settlers flowing into the colony. The Lenape were given permission by the Wyandot people to settle in the Ohio country. One of their settlements was Maguck, built by 1750 on the banks of the Scioto River. Modern Circleville was built to the north of this site.

The frontier explorer Christopher Gist was the first recorded European visitor to the Circleville area. Gist reached Maguck, the small Lenape village of about 10 families on the east bank of the Scioto River, on January 20, 1751. He wrote that he had stayed in the town for four days.

Circleville was founded by European-American settlers during 1810, as migrants relocated westward after the American Revolutionary War. It derived its name from the circular portion of a large, ancient earthwork of what is known now to have been a remnant of the Native American Hopewell culture; the town was built on top of the remains of this. The original town plan integrated Circleville into the remains of the Hopewell earthworks with a street layout 1,100 ft (340 m) diameter circle. This was connected to a 900 ft (270 m) square. These dated from the early Common Era; the Hopewell tradition flourished until about CE500. An octagonal courthouse was built directly in the center circle of the town.

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