1. In 1847, the first organized post office in the state of California opened in San Francisco, on January 21. It was located in a small wooden building and only operated for a few hours each day.

2. January 21, 1972, marked a historically significant moment in California as the landmark case of Roe v. Wade was handed down by the Supreme Court, legalizing abortion nationwide.

3. On January 21, 1895, the Yosemite Valley and Mariposa Grove were officially established as the Yosemite National Park by President Grover Cleveland, to protect the natural beauty and resources of the area.

4. California became the first state in the US to legalize marijuana for medicinal purposes on January 21, 1996. Proposition 215, also known as the Compassionate Use Act of 1996, allowed individuals with certain medical conditions to use marijuana with a doctor's recommendation.

5. In 1911, January 21 became the official date for the inauguration of California governors. Governor Hiram W. Johnson was the first to be inaugurated on this date, after his election in 1910, and the tradition has continued ever since.