Carroll County is a county in the U.S. state of Mississippi. As of the 2020 census, the population was 9,998. Its county seats are Carrollton and Vaiden. The county is named for Charles Carroll of Carrollton, the last surviving signatory of the Declaration of Independence. Carroll County is part of the Greenwood, Micropolitan Statistical Area. Bordered by the Yazoo River on the west and the Big Black River to the east, it is considered to lie within the Mississippi Delta region.