1846 
- American immigrants in Alta California rebel against the Mexican department’s government, raise a flag featuring a grizzly bear (pictured) at El Cuartel de Sonoma, and establish the short-lived (and unrecognized) California Republic
- US Navy Commodore John D. Sloat claims California for the United States during the Mexican–American War, and US Navy Captain John Berrien Montgomery and US Marine Second Lieutenant Henry Bulls Watson of the USS Portsmouth arrives to claim Yerba Buena two days later by raising the American flag over the town plaza
- Washington Allon Bartlett is named alcalde of Yerba Buena
- Yerba Buena doubles in population when about 240 Mormon pioneers arrive, among them Samuel Brannan