Mass Chinese immigration to Mexico began in the 1876, following mass single-male migrations to Cuba and to Peru where they worked as field laborers coolies. Chinese men immigrated mainly to northern Mexico, and the flow of migration increased following the passage of the 1882 Chinese Exclusion Act in the U.S. Some then entered the U.S. illegally, but many more stayed in the borderlands area on the Mexican side, where they entered commerce as entrepreneurs of small-scale businesses, creating dry-goods stores and laundries in mining and agricultural towns, as well as small-scale manufacturing and truck farming. They came to monopolize the small-business sector. Chinese merchant houses were established in Pacific coast ports, such as Guaymas, hiring their country-men. There was significant anti-Chinese feeling in northern Mexico, which intensified during the Mexican Revolution. They were expelled from Sonora in the 1930s and their businesses nationalized.