Sunflower County is a county located in the U.S. state of Mississippi. As of the 2020 census, the population was 25,971. Its largest city and county seat is Indianola. Sunflower County comprises the Indianola, MS Micropolitan Statistical Area, which is included in the Cleveland-Indianola, MS Combined Statistical Area. It is located in the Mississippi Delta region. Mississippi State Penitentiary is located in Sunflower County.