1. State Arbor Day: April 30th is celebrated as State Arbor Day in South Dakota. This day is observed to encourage the planting and care of trees. South Dakota was the first state in the United States to create an official Arbor Day in 1872.

2. Dakota Territory Established: On April 30, 1861, Congress established Dakota Territory, which included what is now North Dakota and South Dakota, as well as parts of Wyoming and Montana. It was later divided into two separate states in 1889.

3. Huron Tornado: On April 30, 2001, a devastating tornado hit the city of Huron in South Dakota, destroying more than 400 homes, damaging more than 300 others, and injuring 36 people. The twister was classified as an F4 tornado, which is one of the strongest types of tornadoes.

4. Homestake Mine: On April 30, 1900, the Homestake Mine became the largest and richest gold mine in North America. It continued operating for over a century, producing more than 40 million ounces of gold before it closed in 2002.

5. Union County Established: On April 30, 1862, Union County was established in South Dakota. It was named in honor of the Union Army during the American Civil War. The county seat is located in Elk Point and the county is home to more than 15,000 residents.