NYPL 1850 San Francisco Post Office
The discovery of gold in 1849 completely transformed the city. San Francisco was overrun with people seeking their fortune in the eastern hills across the Bay. The city's sleepy population swelled from 800 to 25,000 in a matter of months. This image shows a post office swarmed by individuals hoping to change their lives with a nugget of gold. Over 300,000 prospectors came to the Bay area during the period of 1848-1852, with half of them arriving by sea. During this time, California began to build its infrastructure and officially became a State in the Union on September 9th, 1850.