From Ohio History Central
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 Historical Society 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.