The Ohio government authorized the creation of Carroll County on December 25, 1832. The county was named for Charles Carroll, the last surviving signer of the Declaration of Independence. Carroll died in 1833. The county was originally part of Columbiana County. The Fighting McCooks, a family of Union Army volunteers during the American Civil War, resided in the county. One of the McCooks' homes is now an Ohio History Connection site.
Carroll County is located in the eastern portion of Ohio, and it is in the heart of Appalachia. With less than one percent of the county's 395 square miles deemed to be urban, most residents live in rural areas. The county averages just seventy-three people per square mile. The county's largest community is Carrollton, the county seat, which had just over three thousand residents in 2000. Unlike many of Ohio's predominantly rural counties, Carroll County actually experienced a growth in population between 1990 and 2000. In 2000, 28,836 people resided in the county, and increase of almost nine percent since 1990.
Approximately ten percent of Carroll County's residents earn their livings through farming. Manufacturing establishments, sales positions, and service industries are the three largest, non-agricultural employers in the county. Coal mining used to be a major industry in the county, but companies have extracted most of the coal through strip mining. In 1999, the per capita income for Carroll County residents was approximately twenty-one thousand dollars. Almost eleven percent of the county's residents lived in poverty. This percentage is relatively small in comparison to most other counties in Appalachian Ohio.
Most voters in Carroll County claim to be independents, yet in recent years, they have supported Republican Party candidates at the national level.
Ralph Hodgson, a poet, ranks among Carroll County's more famous residents.