Reva, South Dakota Reva, South Dakota Reva is an unincorporated community in Harding County, South Dakota, United States. Although not tracked by the Census Bureau, Reva has been assigned the ZIP code of 57651. The community has the name of Reva Bonniwell, the daughter of a first settler. The Battle of Slim Buttes occurred here on September 9–10, 1876, in the Great Sioux Reservation between the United States Army and Miniconjou Sioux during the Great Sioux War of 1876. It marked the first significant victory for the Army since the stunning defeat of General George Custer at the Battle of Little Bighorn in
Battle of the Little Bighorn size of cavalry companies to 100 enlisted men on July 24. The committee temporarily lifted the ceiling on the size of the Army by 2,500 on August 15. As a result of the defeat in June 1876, Congress responded by attaching what the Sioux call the "sell or starve" rider () to the Indian Appropriations Act of 1876 (enacted August 15, 1876), which cut off all rations for the Sioux until they terminated hostilities and ceded the Black Hills to the United States. The Agreement of 1877 (, enacted February 28, 1877) officially took away Sioux land and permanently established