Chickasaw County is a county located in the U.S. state of Mississippi. As of the 2020 census, the population was 17,106. Its county seats are Houston and Okolona. The county is named for the Chickasaw people, who lived in this area for hundreds of years. Most were forcibly removed to Indian Territory in the 1830s, but some remained and became citizens of the state and the United States.

A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equivalent term, shire town, is used in the U.S. state of Vermont and in several other English-speaking jurisdictions. County towns usually serve a similar function in Ireland, Jamaica, and the United Kingdom.