After the Mexican Revolution (1910-1920), the Mexican government sought to establish a series of frontier schools along the United States-Mexico border in an attempt to keep what officials believed were its most economically valuable citizens from migrating to the United States in search of improved economic and educational opportunities. This article examines the frontier schools in three Mexican states -- Sonora, Chihuahua, and Coahuila -- and four border cities -- Nogales, Ciudad Juárez, Villa Acuña, and Piedras Negras. While each of these states and each of these cities had different relationships with both the Mexican federal government -- which controlled the frontier schools -- and their sister cities on the US side of the border, each of them demonstrates the ways that cross-border mobility increased the ability of Mexicans (and their Mexican-American extended families) to effectively pressure the Mexican federal government to provide the types of social services -- in this case, expanded elementary schooling and co-curricular opportunities -- that they desired.