What was the Gold Rush?

The Gold Rush refers in American usage primarily to the California Gold Rush of 1848 to 1855, the largest mass migration in American history to that point, in which roughly 300,000 people moved to California seeking gold after the discovery at Sutter's Mill in January 1848 transformed the recently acquired territory into a frontier boomtown society and accelerated its admission as a state in 1850.

James W. Marshall, a carpenter working for John Sutter, found gold flakes in the tailrace of a sawmill on the American River at Coloma, California on January 24, 1848, just nine days before the Treaty of Guadalupe Hidalgo of February 2, 1848 transferred California from Mexico to the United States. The discovery was kept quiet briefly, but by mid 1848 the news had spread, and President James K. Polk's December 5, 1848 message to Congress confirmed the discovery and unleashed the rush.

About 80,000 people arrived in California in 1849 alone, the so-called Forty-Niners, traveling by three main routes: overland on the California Trail across the Great Plains and Sierra Nevada, around Cape Horn by sea (a four to seven month voyage), or by ship to Panama, across the isthmus by mule, and by ship up the Pacific coast. Migrants came from across the United States and from China, Mexico, Chile, Australia, Britain, France, and elsewhere. By 1855 some 300,000 had reached California. San Francisco grew from about 1,000 residents in 1848 to about 20,000 by 1850 and 56,000 by 1860. Sacramento became a supply hub.

Gold mining evolved through several phases. Early miners panned and sluiced placer gold from streambeds. As surface deposits ran out by the early 1850s, hydraulic mining began washing entire hillsides into rivers, producing massive environmental damage. Hard rock mining followed underground veins, requiring corporate capital and industrial techniques. Total gold production from California through 1855 has been estimated at about 750 million dollars at contemporary prices, or about 2 billion dollars in 1900s dollars; estimates vary widely.

The Gold Rush had immense political and demographic consequences. It accelerated California's admission as the 31st state on September 9, 1850 as part of the Compromise of 1850, which admitted California as free, organized New Mexico and Utah territories with popular sovereignty on slavery, and passed the Fugitive Slave Act. The rush brutally displaced California Native peoples, whose population fell from about 150,000 in 1848 to about 30,000 by 1870 through massacre, disease, and starvation. Anti-Chinese sentiment grew, leading later to the foreign miners tax of 1852 and eventually the Chinese Exclusion Act of 1882.

Gold rushes followed in Australia (1851), Colorado (1858), Nevada (1859), Idaho (1860), Montana (1862), and the Klondike (1896 to 1899).