Quitman County is a county located in the U.S. state of Mississippi. As of the 2020 census, the population was 6,176, making it the third-least populous county in Mississippi. Its county seat is Marks. The county is named after John A. Quitman, Governor of Mississippi from 1835 to 1836 and from 1850 to 1851. Quitman County is located in the Mississippi Delta region of Mississippi.