In 1849, about 1,000 people lived in California. California was actually part of Mexico. The United States was at war with Mexico. A few days after the discovery of gold, the Mexican-American War ended. As part of the treaty, California became part of the United States. The treaty negotiators did not know that gold had been discovered. They wanted California to be part of the United States because of California's huge coastline on the Pacific Ocean.

From 1849 to about 1859, as the word spread that gold had been discovered in California, people from all over the world headed to California to seek their fortune. We call this the California Gold Rush.