You are probably talking about Chinese immigrants in the United States, who began immigrating into the country in 18th century. Thousands of Chinese workers went to the California Gold Rush looking for work, while thousands more were hired to build the First Transcontinental Railroad. Treatment of Chinese immigrants are particularly harsh since they become targets for populist politicians and white laborers. In 1882, the Chinese Exclusion Act was passed which barred practically all Chinese from entering the United States for 10 years.