1. In 1857, the territorial governor issued a proclamation that officially set September 25 as the day for the first general election in South Dakota. This election paved the way for South Dakota to eventually become a state in 1889.

2. In 1877, the notorious outlaw Jesse James and his gang robbed the First National Bank in Northfield, Minnesota. The robbers fled west into South Dakota, where a group of local farmers and lawmen pursued and captured them two weeks later on September 25.

3. The city of Mitchell, South Dakota is known for its unique attraction, the Mitchell Corn Palace. The first Corn Palace was built in 1892, and every year since then, the building's exterior has been decorated with corn and other grains in a new and elaborate design. On September 25, 1921, the Corn Palace held its first Corn Palace Festival, which has since become an annual tradition.

4. In 1942, the US Air Force established the Rapid City Army Air Base in South Dakota. The base played a key role in training bomber crews during World War II, and today it is the location of Ellsworth Air Force Base, a strategic bomber base that is home to the B-1B Lancer.

5. On September 25, 1960, the University of South Dakota hosted a debate between presidential candidates John F. Kennedy and Richard Nixon. The debate is notable for being the first televised presidential debate in US history, and it had a significant impact on the outcome of the election.