James Marshall discovered gold at Sutter’s Mill in California in 1848, starting the California Gold Rush.
Marshall found flakes of gold on January 24, 1848, while supervising construction of a water-powered sawmill for John Sutter. The mill stood beside the South Fork of the American River near present-day Coloma, in the foothills of the Sierra Nevada.
News spread gradually, and the discovery triggered a mass migration known as the California Gold Rush. California’s non-Indigenous population expanded dramatically, with prospectors arriving from the United States and many other countries. The rush helped accelerate California’s admission to the Union as the 31st state in 1850.
The discovery occurred shortly before the Treaty of Guadalupe Hidalgo transferred California from Mexico to the United States. A common mix-up is naming Marshall rather than the site: Marshall found the gold, but Sutter’s Mill is the canonical location associated with the discovery.