In May 1882, Congress, responding to pressure from unions, passed the Chinese Exclusion Act. This treaty with the Chinese Government banned Chinese emigrants from entering America and called for the deportation of any who arrived after 1880.
Chinese immigrants began arriving in America in significant numbers in the 1850s, most from the southern provinces of China, where war, persecution and famine caused the deaths of millions. American businessmen actively sought Chinese laborers in mines and other industries, using them to provide much of the labor for building the transcontinental railroads. At first praised as diligent workers, praise turned to hostility as the railroad was completed and competition for other jobs increased. Anti-Chinese political activity and violence erupted between 1880-1900 throughout the West, resulting in scores of deaths.