1. Statehood Day Celebration: December 31 marks Statehood Day in South Dakota, the day the state officially became the 40th state in the United States in 1889. To celebrate, special events and activities are held throughout the state each year.

2. Blizzard of 1961: December 31, 1961, was a historic day in South Dakota as a massive blizzard swept across the state. With wind gusts over 70 mph and more than two feet of snow, the storm brought life to a standstill for several days and caused significant damage and loss of life.

3. Wild West Shootout: On December 31, 1876, one of the most famous "wild west" shootouts took place in Deadwood, South Dakota. Known as the "Deadwood shootout," the incident involved legendary figures such as Wild Bill Hickok and Calamity Jane and ended in several fatalities.

4. First Night Festivals: Several communities in South Dakota hold "first night" celebrations on December 31, featuring family-friendly activities, live music, and fireworks displays. The first known first night festival in the state was held in Watertown in 1994.

5. New Year's Eve Ball Drop: Sioux Falls, the largest city in South Dakota, rings in the new year with a countdown and ball drop at the Falls Park downtown. The tradition began in 2010 and has since become a popular event, drawing thousands of spectators each year.