1. In 1890, South Dakota was officially admitted as the 40th state in the United States. May 15 was chosen as Statehood Day, a holiday commemorating the event.

2. The state's largest newspaper, the Argus Leader, was first published on May 15, 1881, in Sioux Falls. The paper is still in circulation today.

3. On May 15, 1961, the first and only hijacking in South Dakota history occurred. A man claiming to have a bomb hijacked a private plane and demanded to be flown to Cuba. The plane eventually landed safely in Florida, and the hijacker was arrested.

4. In 2013, a tornado struck the town of Wessington Springs on May 15, causing significant damage to homes and businesses. Fortunately, no one was killed in the storm.

5. May 15 is also known as Peace Officers Memorial Day, honoring the sacrifices made by law enforcement officers who have given their lives in the line of duty. In South Dakota, the state's Law Enforcement Officers Memorial is located in Pierre and is a place for citizens to honor fallen officers.