1. In 1868, President Andrew Johnson signed the Sioux Treaty of Fort Laramie, which included present-day South Dakota, and established the Great Sioux Reservation.

2. In 1872, the first permanent settlement in the Black Hills of South Dakota was established when gold was discovered in the area. This led to the famous gold rush and the eventual founding of the city of Deadwood.

3. In 1889, South Dakota became the 40th state in the United States, after a controversial referendum and congressional approval. It was also the first state to elect a woman to the U.S. Congress, with the election of South Dakota's Jeannette Rankin in 1916.

4. In 1936, the world's only Corn Palace was dedicated in Mitchell, South Dakota. The building is decorated with corn and other grains each year in a different design, and hosts events and concerts.

5. In 1984, the United States Supreme Court issued a landmark ruling in the case of Cheyenne River Sioux Tribe v. South Dakota, which affirmed the right of Native American tribes to exercise criminal jurisdiction over non-Native Americans on tribal lands. This decision has had a significant impact on the relationship between Native American communities and law enforcement in South Dakota and across the country.