This article examines the development of racially segregated Mexican rooms and Mexican schools in Wyoming during the Depression era. Working in concert with New Deal legislation, the segregation of Mexican children--regardless of US citizenship--in Wyoming was not just a matter of social practice and local custom, it became an expression of increased state and federal power that mirrored Jim Crow laws. Wyoming was not alone. The segregation of Mexicans also occurred in neighboring Colorado, Montana, and Nebraska. This article also discusses how, ultimately, public schools and schooling finalized the codification and institutionalization of Mexicans as a race of their own. In Wyoming, schools were the architects of the Mexican race. Furthermore, this unexplored area demonstrates that the segregation of Mexican children was not just a Southwest phenomenon but encompassed almost all of the US West.