The United States now hosts its largest immigrant population in history, totaling 53.3 million people.

Nature · Published 30 September 2026 Swipe more like this →

In short: With 53.3 million foreign-born residents as of early 2025, the United States holds the world's largest immigrant population. This record-breaking figure represents 15.8% of the total population, a demographic shift that has defined the nation's history, economic trajectory, and ongoing political debates regarding security, labor, and national identity.

The United States is fundamentally an immigration country, shaped by four distinct historical epochs: the colonial period, the mid-19th century, the turn of the 20th century, and the post-1965 era. While early colonial migration was dominated by English settlers—who accounted for over 83% of the white population by 1790—the 20th century saw the introduction of restrictive quota systems. The Immigration Act of 1924, for instance, used the National Origins Formula to preserve a specific demographic makeup based on 1920 census data, effectively curtailing immigration from Southern and Eastern Europe and banning most Asian immigration.

The 1965 Hart-Celler Act marked a pivotal shift by abolishing these national-origin quotas, which ultimately diversified the immigrant population. By 2000, the share of immigrants from Europe had dropped to 15%, down from 60% in 1970. Modern policy has increasingly prioritized skilled labor, particularly in STEM fields, while simultaneously grappling with the complexities of unauthorized migration. As of March 2025, estimates suggest approximately 18.6 million illegal immigrants reside in the U.S., a group that faces limited legal avenues for entry due to restrictive green card caps.

The economic and social impact of these trends remains a subject of intense controversy. Research generally suggests that immigration provides a net benefit to the U.S. economy, though low-skilled natives may face adverse effects. Despite political rhetoric often framing immigrants as security threats or criminals, studies consistently show that immigrants have lower crime rates than native-born citizens. Policies have evolved from the 1986 amnesty for 3 million people to the more recent, contentious enforcement strategies of the 21st century, including border barrier proposals and family separation policies, reflecting a persistent tension between the nation's reliance on immigrant labor and its desire for border control.

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