How did migrants from northern Argentina, Bolivia, and Paraguay change Buenos Aires after 1930?

After 1930, the character of Buenos Aires underwent significant changes due to the virtual halt of international immigration, which shifted the city's labor supply toward domestic and regional migrants.1

The primary impacts of this migration include:

• Demographic Shift: The demand for labor in the metropolitan area was increasingly met by migrants from northern Argentina and the neighboring countries of Bolivia and Paraguay. These newcomers were predominantly mestizo, adding a new ethnic dimension to the city's population.12
• Urban Development: As inner-city housing became overcrowded, these migrants settled on unoccupied suburban land near manufacturing centers. This led to the emergence of villas miserias (shantytowns), which became a lasting feature of the metropolitan landscape.1
• Social and Political Conflict: The arrival of these migrants introduced new social tensions, as their ethnic and cultural differences often led to conflicts with the porteños (residents of Buenos Aires). These social divisions were exacerbated by the development of industrial capitalism during the 1930s, ’40s, and ’50s, and many of these newcomers became staunch supporters of the populist leader Juan Perón.1

These developments fundamentally altered the social fabric of the city, creating a persistent divide between the established population and the newer migrants.12