Gold was first discovered on the banks of the American River in California by carpenter James W. Marshall in January 1848, and word spread quickly of the discovery. By the end of 1849, around 80,000 people had travelled to the area in search of gold, and the nascent industry helped merchant Sam Brannan establish himself as California’s first millionaire, selling mining supplies to the thousands of miners who flowed into the state.
Production peaked in the decades following the discovery. In 1853, miners from as far afield as South America, Europe and China are all reported to have made their way to the state, and the total value of the mining industry in the area is said to have reached half a million dollars between 1870 and 1880.
The US National Park Service (NPS) reports that in the area that is now Joshua Tree National Park, 300 individual mines were established across the 3,200 km² region.
One of the best-preserved mines in the park is the Lost Horse Mine, which was established in 1890 and produced around 10,000 ounces of gold, and 16,000 ounces of silver, between 1894 and 1931. The NPS estimates that the value of the minerals would be around $5m today; since the end of operations in 1936, the mine has become a popular tourist destination for travellers to the area.