The Gold Rush Mexico cedes California to the United States. The gold discovery brings people from many countries. American citizens cross the plains, sail around the Horn and cross the Isthmus. Immigrants arrive from China, and are barred from the mines. African-Americans come to the mines, some leave California for British Columbia.
Steamboats fill the rivers.
The Port of San Francisco becomes notorious for shanghaiing sailors. The Indian population shrinks. The Southern Pacific monopolizes rail traffic to and from California. Farmers rebel against high-handed railroad tactics. After ten years of depression, the boom begins again.