1. May 13, 1804 - The date when the Lewis and Clark expedition arrived in present-day South Dakota. On this day, the explorers entered the territory of the Yankton Sioux tribe, where they built a fort and met with local chiefs.

2. May 13, 1862 - The Battle of Vermillion Springs took place in southeastern South Dakota during the Dakota War of 1862. Dakota warriors attacked a supply train headed for Fort Dakota, killing eight soldiers and two civilians.

3. May 13, 1888 - South Dakota became the first state to institute a statewide prohibition on the sale of alcoholic beverages. The law went into effect on July 1 of that year and remained in place until the end of Prohibition in 1933.

4. May 13, 1934 - South Dakota State University was officially renamed from South Dakota State College to reflect its expanding academic programs and research activities.

5. May 13, 2010 - The first tornado of the 2010 season struck South Dakota near the town of Grandview, causing extensive damage to buildings and crops. The storm was part of a larger outbreak across the central United States that produced 45 tornadoes in one day.