Lee County is a county located in the U.S. state of Arkansas. With its eastern border formed by the Mississippi River, it is considered to be part of the Arkansas Delta. As of the 2020 census, the population was 8,600. The county seat is Marianna. The county was established by the state legislature on April 17, 1873, during the Reconstruction era. It was named for General Robert E. Lee, who served as General in Chief of the Armies of the Confederate States during the American Civil War.