How Many Unauthorized Immigrants Live in the United States? A Look at the Numbers and Root Causes
Unauthorized immigration continues to be one of the most discussed—and often misunderstood—topics in American public discourse. From politicians to policymakers, journalists to the general public, many seek clarity on how many people reside in the United States without legal status and how they came to be in this position. But what do the numbers really say, and what is the main source of illegal immigration?
How Many Unauthorized Immigrants Are in the U.S.?
Estimates vary depending on the methodology and definitions used, but two respected organizations offer contrasting figures:
Pew Research Center estimates that there were approximately 11 million unauthorized immigrants in the United States as of 2022. This number reflects a modest increase from 2019 but remains lower than the peak of 12.2 million recorded in 2007.
Federation for American Immigration Reform (FAIR) provides a much higher estimate. According to their 2025 update, approximately 18.6 million unauthorized immigrants are currently in the U.S., an 11% increase from the previous year.
The differences in these numbers stem from how each organization defines “unauthorized” and which data sources they rely on. Pew tends to use more conservative estimates derived from U.S. Census and American Community Survey data, while FAIR includes broader categories and relies on additional sources.
Regardless of the exact number, it is clear that millions of people are living in the United States without formal immigration status—impacting communities, policy decisions, and the broader economy.
What Is the Main Source of Illegal Immigration?
Contrary to popular belief, the majority of unauthorized immigrants in recent years did not cross the border illegally. Instead, most entered the U.S. legally and overstayed their visas.
This phenomenon is often referred to as "visa overstay", and it has quietly become the dominant source of unauthorized presence in the country. According to the U.S. Department of Homeland Security, roughly 40–50% of all people living in the U.S. without status came in through legal ports of entry—on tourist visas, student visas, work permits, or other temporary authorizations—and did not leave when their visa expired.
The remaining group typically consists of individuals who crossed the southern U.S. border between official ports of entry, often seeking employment opportunities or fleeing instability in their home countries.
Why Do People Overstay Their Visas?
There are many reasons why someone might overstay a visa:
Economic Hardship: Some individuals find better employment or business opportunities in the U.S. and remain longer than permitted.
Family Reunification: A person may stay to support or be with family already residing in the U.S., whether legally or not.
Fear of Returning Home: Conditions in the home country—such as war, political persecution, or lack of security—may make returning dangerous or undesirable.
Systemic Delays: In some cases, individuals apply for status changes or asylum, but delays in processing leave them in legal limbo.
Addressing the Issue: Policy Challenges
Understanding the real source of unauthorized immigration is essential for crafting effective policy. Efforts that focus solely on physical border security miss the broader challenge posed by visa overstays, which often require improvements in tracking systems, legal pathways to permanence, and processing times for immigration applications.
It’s also important to note that many people living without status contribute positively to U.S. society—working, paying taxes, and raising families. Any serious discussion about immigration reform must consider both border integrity and the humane treatment of long-term residents who are integrated into American communities.
Conclusion
The number of unauthorized immigrants in the United States is significant, whether the figure is 11 million or closer to 18 million. While illegal border crossings do occur, visa overstays are now the leading source of unauthorized presence. Understanding this reality is essential for developing informed and compassionate immigration policies that reflect the complexities of migration and human behavior.