1. In 1889, South Dakota officially became a state on October 4th, after joining the Union alongside North Dakota. Both states were admitted on the same day, making them the 39th and 40th states, respectively.

2. The Crazy Horse Memorial in the Black Hills of South Dakota was dedicated on October 4th, 1948. The massive sculpture, which is still under construction today, features the Oglala Lakota warrior and leader Crazy Horse mounted on a horse.

3. On October 4th, 1987, South Dakota Senator Larry Pressler became the first Republican senator to publicly call for President Ronald Reagan's resignation over his involvement in the Iran-Contra scandal. Pressler was later praised for his stance and for being willing to stand up to his own party.

4. October 4th, 1997, marked the unveiling of a new six-story building for the Sanford School of Medicine at the University of South Dakota in Sioux Falls. The building was named after T. Denny Sanford, a philanthropist who donated $25 million toward its construction.

5. In 2013, South Dakota Governor Dennis Daugaard designated October 4th as "Korean War Veterans Recognition Day" to honor the more than 33,000 South Dakotans who served in the Korean War. The day is now recognized annually in the state as a way to show appreciation for veterans' sacrifices and dedication to the country.