1. The Battle of Tongue River occurred on August 25, 1865, in southeastern Montana, near the South Dakota border. The battle was fought between the Sioux tribe and the U.S. Army and resulted in a victory for the Sioux.

2. On August 25, 1876, Wild Bill Hickok was shot and killed in Deadwood, South Dakota. Hickok was a legendary figure of the American West and is remembered for his skills as a gunfighter and lawman.

3. In 1943, the U.S. Army Air Force established Rapid City Army Air Base near Rapid City, South Dakota. The base was later renamed Ellsworth Air Force Base in honor of Brigadier General Richard E. Ellsworth, who was killed in a crash of a B-52 bomber in Spain in 1953.

4. On August 25, 1966, the Black Hills Flood occurred in Rapid City, South Dakota. The flood was caused by a combination of heavy rain and a rapid snowmelt, and resulted in 238 deaths and $160 million in damages.

5. The annual Sturgis Motorcycle Rally, one of the largest motorcycle events in the world, usually begins on the first Monday in August and lasts for 10 days. Therefore, August 25 is often in the middle of the rally, and visitors can enjoy a wide array of entertainment, including concerts, races, and shows.