1. On December 16, 1826, Peter Skene Ogden and a party of trappers established Fort Langley in present-day British Columbia, Canada. However, Ogden was working for the Hudson's Bay Company, which at the time had significant holdings in what is now Oregon.

2. In 1850, the Willamette Valley Treaty was signed between the United States government and several tribes of Oregon's Willamette Valley. The treaty ceded the land to the United States, but allowed the tribes to retain certain rights on their traditional territories.

3. On December 16, 1864, the Oregon State Agricultural Society was founded in Salem. The organization played a crucial role in the development of Oregon's agriculture by promoting research, education, and innovation.

4. In 1920, the Oregon State Capitol was completed in Salem. The building, which is still in use today, features an impressive dome made of copper and is considered one of the most beautiful Capitol buildings in the United States.

5. On December 16, 1985, the landmark case of State v. Stroup was decided by the Oregon Supreme Court. The case dealt with the issue of whether or not a medical marijuana user could be prosecuted for possession, and ultimately established the legality of medical marijuana in the state.