In 1848, James W. Marshall discovered gold at Sutter's Mill in California. Immigrants from around the world rushed to the new territory, where, at that point, gold was so plentiful one could practically pick it off the ground. These people, labeled 49ers, caused a major population boom. Over 300,000 people came to California. This, more often than not, forced the natives to relocate. Eventually, the rush died down as the gold ran out.