On February 2, 1848, the American-Mexican War ended with the signing of a treaty that left California in the hands of the United States. Eight days before, carpenter James Marshall had found flakes of gold in the American River in the Sierra Nevada mountains while building a sawmill of John A. Sutter, who owned a ranch in Sacramento Valley. To test if it was gold, Marshall tried to break the nugget between two rocks - only to find out that it could change shape, but not broken. He was sure that what he had discovered, was gold.
Marshall and Sutter tried to keep the discovery for themselves, but Mid-March, a San Francisco newspaper published an article reporting that gold had been found at Sutter's Mill. Within two weeks, the paper's staff had left to go to Sutter's creek. They were soon followed by about 75% of the male San Francisco population, who turned their backs on their fields and labors in the expectancy of making quick fortune with finding gold. By August, some 4,000 miners had reached the area.
The news soon spread worldwide, and by 1849, 80,000 men from the Americas, Britain, Australia, Europe and China arrived in California by ship or by the Californian trail. The would-be gold-miners migrating were called "forty-niners". The California population rose to over 200,000 in less than three years. Few women accompanied their husbands in the early years, and they took on the responsibility of running farms and businesses.
All those men needed lodging; camps and gold mining towns popped up all over the region. Abandoned ships in San Francisco Bay also were converted to temporary housing. Businessmen used the "Gold Rush" immigration flow, and large numbers of saloons, shops and brothels were established. In San Francisco alone, there soon were over 500 bars and 1000 gambling houses.
These male communities were prone to violence and drunkenness. Mining towns were highly lawless: gambling, prostition, robbery, murder and mistreatment of Chinese, Mexicans and Indians were the order of the day. A thousand murders were committed in San Francisco in the 1850s - Indians were killed for sport, for example. Since there were no courts, the communities developed their own legal system and judgement was often handed out by popular vote.
The gold rush radically changed California. The population had grown immensely in a short time and the economy had gotten a big boost. Not only bar keepers and miners, but also metal specialists, doctors and merchants were brought in. Over a $200 million in gold was found in five years, but most of the migrant miners went home broke, just because there were too many of them. When gold was more difficult to extract, industries took over the independent miners into wage labor. Hydraulic mining, a technique developed in 1853, led to high profits, but also destroyed much of the landscape.
Most of the mining towns were abandoned as quickly as they had risen and turned into ghost towns. Some of them can still be visited today.