The first significant wave of Italian immigrants came to California during the Gold Rush. Those who came quickly moved to buy land or work in service industries, rather than stay in the mines. In 1850, there were 229 Italians in San Francisco. By 1860, the largest number of Italian immigrants in the United States lived in California, and, as late as 1890, there were more Italian immigrants in the Pacific coast states than in New England. With these numbers, Italians began building communities in California. They introduced Italian Opera to California in 1851, and founded an Italian language newspaper in San Francisco as early as 1859. Mutual aid societies, based on the model of the French immigrant community in San Francisco, were formed. Italian priests founded the University of San Francisco in 1856. The first Columbus Day celebration in San Francisco occurred in 1869, as a celebration of "the first Italian-American." That Columbus was from Genoa was a particular source of pride for Italians in San Francisco. In spite of these successes, the Italian community in California remained small.
The aftermath of the Gold Rush brought more northern Italians to California. The ostentatious wealth of those who succeeded during the Gold Rush years brought with it a demand for stone and marble cutters from Italy to work on the mansions of the newly rich. The fishing grounds and warm climate began to attract Sicilian fishermen for the first time. At the same time, northern Italian immigrants who were able to save a little began to buy real estate in the valleys for agriculture. Wine wasn’t the only agricultural product developed by Italians in California. Eating grapes and citrus fruits were also grown in the rich California soil. Small truck gardens, stored on the outskirts of San Francisco became a popular way for new immigrants to make a living. Other immigrants, such as Domenico Ghirardelli, began to specialize in grocery items, such as chocolate.