Between 1849 and 1852, the population of California more than doubled. California saw a population boom in the mid-1800s due to the California Gold Rush, which began in 1848. Thousands of people flocked to California in search of gold, which led to a population boom in the state.What was the California Gold Rush?The California Gold Rush was a period of mass migration to California between 1848 and 1855 in search of gold. The gold discovery at Sutter's Mill in January 1848 sparked a gold rush that drew thousands of people from all over the world to California. People from all walks of life, including farmers, merchants, and even criminals, traveled to California in hopes of striking it rich. The Gold Rush led to the growth of California's economy and population, and it played a significant role in shaping the state's history.