1. In 1783, Delaware became the first state to ratify the Articles of Confederation, which was the first constitution of the United States.

2. On December 20, 1860, Delaware Governor William Burton delivered his final speech to the state legislature. In it, he expressed his support for the Union and his opposition to secession.

3. The State of Delaware officially adopted its flag on December 20, 1913. The flag features a coat of arms depicting a farmer and a soldier along with the state motto, "Liberty and Independence."

4. The Delaware Memorial Bridge, a suspension bridge spanning the Delaware River and connecting Delaware and New Jersey, opened to traffic on December 20, 1951. At the time of its construction, it was the longest suspension bridge in the world.

5. On December 20, 2019, Delaware Governor John Carney signed into law a bill allowing Delaware residents to earn a high school diploma by passing a high school equivalency exam, such as the GED. This provided an alternative pathway to graduation for individuals who left high school before earning a diploma.