The California Gold Rush occurred between 24 January 1848 and 1855, after gold was discovered at Sutter's Mill in Coloma, California. The news of the Gold Rush brought 300,000 people to California from the rest of the United States and abroad, reinvigorating the American economy; these migrants sought to become rich by finding and selling gold. Prospectors retrieved the gold from streams and riverbeds using simple techniques such as panning, and more sophisticated methods of gold recovery were invented and adopted across the world.
In 1850, California directly acquired statehood without having to be a territory, as the waves of immigrants allowed for it to be quickly incorporated. The Native Americans were eradicated by disease, genocide, and starvation caused by the mass influx of settlers. The thinly populated ex-Mexican territory became home to the first Republican Party presidential nominee, John C. Fremont, and it also attracted tens of thousands of immigrants from Latin America, Europe, Australia, and China. Agriculture and ranching expanded throughout the state to meet the needs of the settlers, and San Francisco grew from a settlement of 200 settlers in 1846 to a boom town of 36,000 by 1852. By 1869, railroads were built across the state and the rest of the country as a result of the large-scale migration. A few people achieved great wealth, but many returned home with little more than they had started with, as the wealthy kept the gold and its profits for themselves.