Angel Island is probably best known as the home of the Angel Island Immigration Station. The station, which operated from 1910 to 1940, was the main entry point into the United States for people arriving from the Pacific routes. More than one million people were processed at the station; most were allowed to enter the United States immediately and did not spend much, if any, time on the island. Rather, they were allowed to enter San Francisco soon after their ships docked, and their paperwork was forwarded to the immigration station for processing and storage.

Because so many people were processed there, Angel Island is often called America's "Ellis Island of the West." This name is not accurate, however, due to an important difference in the missions of the two immigration stations. On Ellis Island, immigrants were welcomed to the United States, and the vast majority were processed and landed immediately. On Angel Island, however, many immigrants--most of whom were Chinese--were not welcomed at all and were allowed into this country only grudgingly. The Chinese exclusion laws, first passed in 1882 and updated periodically until 1943, were enacted to keep Chinese immigrants out of the United States. During the twentieth century, several other Asian ethnic groups were added as well to the "excluded" list.

In the mid- to late nineteenth century, large numbers of Chinese people were coming to the United States, drawn initially by the gold rush to San Francisco and Gam Saan (the Gold Mountain) then to work as inexpensive laborers on the transcontinental railroad and in mines in the western part of the country. Many American-born workers perceived these laborers as having taken jobs away from them, and when an economic depression hit the United States in the 1870s, the anti-Chinese sentiment increased enormously. In response to public opinion, Congress passed the exclusion laws.

In enforcing these laws, immigration officials detained newly arrived Chinese people while they determined their eligibility to enter the United States. According to some estimates, 75 to 80 percent of the arrivals were admitted to the United States after some form of detention. Most detention periods ranged from few days or a couple of weeks to six months; a few lasted as long as nearly two years. Regardless of the length of time, detainees had little, if any, contact with friends or relatives on the mainland. For this reason, the immigration station on Angel Island was known among Immigration Service officials as the "Guardian of the Western Gate."

The first laws barred the immigration of Chinese laborers for ten years: "Whereas in the opinion of the Government of the United States the coming of Chinese laborers to this country endangers the good order of certain localities within the territory thereof . . . the coming of Chinese laborers to the United States . . . is hereby suspended, and during such suspension it shall not be lawful for any Chinese laborer to come . . . [to] the United States." The law was also explicit regarding matters of citizenship for Chinese people: "hereafter no State court or court of the United States shall admit Chinese to citizenship."

The exclusion laws granted exemptions to certain groups of Chinese people. Teachers, consular officials, tourists, merchants, and the wives and children of exempt individuals were allowed to enter the United States. This last group of exempt people were generally the relatives of American-born Chinese or of those Chinese people who had been naturalized prior to the passage of the law and who had left families behind in China when they immigrated to the United States. Sometimes, however, Chinese men returned to China, married, and brought their wives to the United States.

In 1888 Congress passed another law, restricting a Chinese person's right to travel: "No Chinese laborer in the United States shall be permitted, after having left, to return thereto." Again, as with the original exclusion laws, there were exceptions to this law. Individuals whose wives or children resided in the United States and those whose assets in this country were greater than one thousand dollars were allowed to leave and return.

The exclusion laws were renewed in 1892, with additional provisions. The most restrictive one required all Chinese laborers legally residing in the United States to obtain certificates of residence that offered proof of their legal status. Any Chinese laborer without such a certificate would be subject to arrest and deportation. Laws similar to these were also adopted around the turn of century in the Hawaiian territories.