Attala County /ˈætələ/ is a county located in the U.S. state of Mississippi. As of the 2010 census, the population was 19,564. Its county seat is Kosciusko. Attala County is named for Atala, a fictional Native American heroine from an early-19th-century novel of the same name by François-René de Chateaubriand.The historian of the American Civil War, John D.