1. 1889: South Dakota Becomes a State
On August 31, 1889, South Dakota was admitted to the Union as the 40th state. This followed the passage of the Enabling Act by Congress, which empowered the people of the Dakota Territory to form a state government.

2. 1952: Mount Rushmore National Memorial Dedicated
On August 31, 1952, the Mount Rushmore National Memorial was officially dedicated in the Black Hills of South Dakota. The monument, which depicts the faces of Presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln, is one of the most iconic landmarks in the United States.

3. 1972: The South Dakota Flood
On August 31, 1972, a severe flash flood hit the city of Rapid City, South Dakota, causing significant damage and loss of life. The flood was caused by a heavy rainstorm, and the resulting floodwaters destroyed over 1,300 homes and killed 238 people.

4. 1999: Grand Opening of the Denny Sanford Premier Center
On August 31, 1999, the Denny Sanford Premier Center in Sioux Falls, South Dakota, opened its doors for the first time. The 12,000-seat arena is now a major venue for concerts, sporting events, and other entertainment attractions.

5. 2020: Joe Biden Visits South Dakota
On August 31, 2020, Joe Biden, the Democratic nominee for President in the 2020 election, visited South Dakota. Biden spoke with residents and local officials about issues such as COVID-19, the economy, and racial justice. His visit marked the first time a Presidential candidate had visited the state in over a decade.