1. Statehood Day: November 18, 1889 was the day that South Dakota officially became the 40th state in the United States. As a result, it is celebrated as Statehood Day every year.

2. Tractor Museum Day: November 18 is also designated as Tractor Museum Day by the state of South Dakota. The state is home to several agriculture and tractor museums, including the Prairie Village Museum in Madison and the Pioneer Auto Show and Prairie Town in Murdo.

3. Laura Ingalls Wilder: Famous author Laura Ingalls Wilder was born in Pepin, Wisconsin on November 18, 1867. Although she did not live in South Dakota herself, her books, including Little House on the Prairie, have become beloved classics in the state and celebrate the pioneer spirit of the Great Plains.

4. Crazy Horse Memorial: November 18, 1939 was the day that construction began on the Crazy Horse Memorial, a massive mountain carving that honors the Lakota warrior and leader. The monument, located in the Black Hills, is still a work in progress and is expected to take several more decades to complete.

5. Badlands National Park: Finally, the Badlands National Park was established on November 18, 1978. The park is known for its rugged terrain, unique rock formations, and diverse wildlife, including bison, bighorn sheep, and pronghorn antelope. It is a popular destination for hikers and outdoor enthusiasts.