The Mormons faced persecution in the eastern United States and moved west seeking religious freedom. Their leader Brigham Young led them to Salt Lake Valley in Utah in 1847 to establish a safe haven. The discovery of gold in California in 1848 triggered the Gold Rush, drawing thousands of prospectors from around the world. San Francisco boomed as a result but also struggled with lawlessness. California drafted a state constitution and joined the Union in 1849. Its diverse population was comprised originally of Native Americans, Mexicans, and later large numbers of Chinese and other immigrants during the Gold Rush.