Tattnall County is a county located in the southeast portion of the U.S. state of Georgia, located within the Magnolia Midlands, a part of the Historic South region. As of the 2020 census, the population was 22,842. The county seat is Reidsville. Tattnall County was created on December 5, 1801, from part of Montgomery County, Georgia by the Georgia General Assembly.

Reidsville is a city in, and county seat of, Tattnall County, Georgia. The population was 2,515 in 2020. The Georgia State Prison is near Reidsville.