James Marshall discovered gold on the American River in February 1848, shortly after the United States acquired California through a controversial war with Mexico. The gold rush, as it quickly became known, thoroughly transformed California in terms of its economic potential, social diversity, and significance to the United States. In 1850, California became a state in record time, owing in part to its mineral wealth and also its rapid population growth. More than 100,000 people arrived in California during 1849. Most planned to mine gold and acquire quick wealth; very few of them were so fortunate.

Although the gold rush was certainly an event of monumental importance to California and the United States, it was also an international phenomenon from the outset. Hopeful miners arrived from all around the world. The first groups to hear the news were those who lived and/or worked around the Pacific Ocean: people in Hawaii, Mexico, South America, China, and Australia. Therefore, the gold rush contained a clear Pacific context even in its origins and initial development. The primary sources collected in this project shed light on the gold rush as a pivotal event in the context of the Pacific World of the mid-nineteenth century.