On January 24, 1848, James W. Marshall discovered gold on the property of Johann A. Sutter near Coloma, California. A builder, Marshall was overseeing construction of a sawmill on the American River.
Previous claims of gold in California had proven disappointing, and Marshall's find was met with skepticism at first. The Gold Rush began in earnest only after President James Polk endorsed the discovery in December 1848. Prospectors heading to California the following year were dubbed "forty-niners."