In a message to the United States Congress, U.S. President James K. Polk confirms that large amounts of gold had been discovered in California.

The California Gold Rush (1848–1855) was a transformative event in American history, sparked by the discovery of gold at Sutter’s Mill in Coloma, California, in January 1848. This discovery triggered a mass migration of prospectors, known as “forty-niners,” who flooded into the region in search of fortune. The population of California skyrocketed, shifting from a sparsely inhabited territory to a booming economic hub. The Gold Rush accelerated California’s admission to the Union as the 31st state in 1850 and fueled significant infrastructure development, including transportation and commerce. However, it also brought environmental degradation, displacement of Native American communities, and violent clashes over land and resources. While a few struck it rich, most prospectors found only modest success, with many transitioning to other occupations, laying the foundation for California’s diverse economy.