1. On December 20, 1823, the first fur trading post was established by the American Fur Company in what is now Fort Union Trading Post National Historic Site. The post was a key location for fur trading between Native Americans, Europeans, and Americans in the early 19th century.

2. In 1886, the Dakota Territory was divided into North and South Dakota by an act of Congress, making December 20 an important date in the state's history. North Dakota became a state in 1889 after Congress passed the Enabling Act, which allowed the people of the territory to form a state constitution.

3. December 20, 1957, is notable as the day that North Dakota's first commercial oil well was drilled in the Williston Basin. The discovery of oil in North Dakota sparked an economic boom that transformed the state's economy.

4. On December 20, 1939, the U.S. Department of Agriculture designated Grand Forks, North Dakota, as the site for the Northern Great Plains Research Laboratory. The laboratory's mission was to conduct research on the ecology and agriculture of the Northern Great Plains, an important region for U.S. food production.

5. In 2012, December 20 was declared "Dale Brown Day" in North Dakota in honor of the legendary basketball coach who led the North Dakota State University men's basketball team to two NCAA Division II championships in the 1970s. Brown went on to coach at Louisiana State University and is considered one of the most successful coaches in college basketball history.