This graph shows the population growth in San Francisco from 1830-1870. Before the gold rush started (1849), San Francisco had barely any people living there, it was just a small town with nothing interesting about it. However, when gold was discovered in 1848, the population started to rise in numbers. By 1849, the number of people in San Francisco had a huge difference from last year. This was the beginning of the gold rush. As the news of gold spread even more, people from around the world came to San Francisco, booming the population by thousands. In 1870, the population was around 150,000 (according to the graph), an immense contrast from 1830.

Video Link

http://www.history.com/shows/america-the-story-of-us/videos/gold-rush