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
Great Sioux War of 1876 Ash Creek. Miles' continuous campaigning pushed a number of the Northern Cheyenne and Lakota to either surrender or slip across the border into Canada. Miles later commanded the US Army during the Spanish–American War. The Agreement of 1877 (, enacted February 28, 1877) officially took away Sioux land and permanently established Indian reservations. While military leaders began planning a spring campaign against the Lakota and Northern Cheyenne who had refused to come in, a number of diplomatic efforts were underway in an effort to end the war. After the defeat at the Battle of the Little Bighorn in June 1876,