Records of the Immigration and Naturalization Service, Series A: Subject Correspondence Files, Part 2: Mexican Immigration, 1906-1930approximately 17,000 pages of U.S. Bureau of Immigration case files that offer substantial information on Mexican immigration from 1900 to 1932, during a period when the Mexican-born population of the United States grew from 103,000 to over 1,400,000. The Mexican Revolution, job opportunities during World War I, and long-term transformations in U.S. industry and agriculture all contributed to Mexican immigration to the United States during this time period. Collection materials document the influx of Mexican immigrants across the borders of Texas, New Mexico, Arizona, and California, as well as immigrants from other countries who also entered the United States by way of Mexico.