The California Gold Rush began when James W. Marshall found gold at Sutter’s Mill in Coloma, California. The news brought approximately 300,000 people to California from the rest of the United States and abroad. These 'forty-niners' (referring to the peak year of 1849) traveled by sailing ship and covered wagon, often enduring extreme hardships. The event transformed California from a sparsely populated territory into a state within two years. It led to the rapid development of San Francisco, the construction of the First Transcontinental Railroad, and significant technological advances in mining. However, it was catastrophic for the Native American population, who faced displacement and violence. The Gold Rush remains a quintessential symbol of the 'American Dream' and the rapid westward expansion of the United States.