Estimating the number of undocumented immigrants in the United States is not a straightforward process. Because this population does not self-identify in official government counts and actively avoids many forms of documentation, researchers and government agencies rely on indirect methods to arrive at their figures. The result is that estimates vary significantly depending on who is doing the counting, what data sources they are using, and how they define the undocumented population.
What is clear from every major research organization and government agency is that the unauthorized immigrant population in the United States is substantial and has changed significantly over the past decade. If you are an immigrant injured in an accident, you can still seek legal guidance from a Houston personal injury attorney about your rights and potential claim. This guide breaks down the most credible estimates, explains why they differ, and covers current immigration enforcement trends.
Current Estimates of the Undocumented Immigrant Population
No single official number exists for how many undocumented immigrants live in the United States, but several respected research organizations publish regular estimates that give a reasonable picture of the population size.
- Pew Research Center, one of the most widely cited sources on immigration data, estimated that the unauthorized immigrant population reached a record high of 14 million in mid-2023, representing the largest two-year increase in more than 30 years The Global Statistics
- The Center for Immigration Studies estimated 14.8 million illegal immigrants as of May 2025, noting that this figure was approximately one million fewer than their January 2025 estimate, suggesting a measurable decline early in the year Pew Research Center
- The Federation for American Immigration Reform published a higher estimate of 18.6 million as of early 2025, using a methodology that accounts for what they describe as systematic undercounting in Census Bureau surveys Wikipedia
- The Migration Policy Institute estimated 13.7 million unauthorized immigrants as of mid-2023, and noted that 80 percent of that population had lived in the United States for five or more years, with 45 percent having been in the country for at least two decades
The most conservative and widely accepted mainstream estimate sits around 11 to 14 million, while higher estimates that account for undercounting range up to 18 million or beyond.
Why Do Estimates Vary So Much?
The gap between the lowest and highest estimates comes down to methodology and how researchers handle the significant undercounting problem that affects all surveys of this population.
The primary tool used by most researchers is the Census Bureau’s American Community Survey, which collects data on the foreign-born population but does not ask about legal status directly. Researchers then subtract the estimated legal immigrant population from the total foreign-born count to arrive at an unauthorized estimate. The problem is that many undocumented immigrants avoid participating in surveys entirely, which means the base data is already incomplete before any calculations are made.
Higher estimates, such as those published by FAIR, apply additional adjustments to account for this undercounting and typically arrive at figures significantly above what Pew Research or the Migration Policy Institute report. Neither approach is without limitation, which is why no single number should be treated as definitive.
Where Do Undocumented Immigrants Come From?
The origins of the undocumented population in the United States have shifted significantly over the past two decades, moving away from a predominantly Mexican-origin population toward a far more diverse group of nationalities.
- Mexico remains the largest single country of origin, though the Mexican undocumented population has actually declined from its peak and now represents a smaller share of the total than it once did
- Central American countries including Guatemala, Honduras, and El Salvador represent a large and growing portion of recent unauthorized arrivals, driven by economic conditions and security concerns in those countries
- Caribbean nations including Cuba, Haiti, Nicaragua, and Venezuela have contributed significantly to recent unauthorized population growth, particularly through humanitarian parole programs that were later rescinded
- Asian countries including India, China, and the Philippines contribute a substantial portion of the visa overstay population, which makes up a meaningful share of the total unauthorized count
- South American countries have also contributed growing numbers, particularly from Venezuela, Colombia, and Ecuador in recent years
Which States Have the Largest Undocumented Populations?
Undocumented immigrants are not evenly distributed across the United States. They are concentrated in states with large labor markets, established immigrant communities, and significant agricultural or service sectors.
- California consistently holds the largest undocumented population of any state, estimated at over 2 million individuals
- Texas ranks second nationally and is home to one of the largest concentrations of undocumented immigrants in the country, particularly in Houston, Dallas, and the Rio Grande Valley
- New York, Florida, New Jersey, and Illinois round out the states with the highest unauthorized populations by total count
- On a per capita basis, states like Nevada, California, and New Jersey have among the highest shares of undocumented residents relative to their total populations
For Texas residents dealing with issues related to undocumented status and access to services, our blog on Houston undocumented immigrants and Medicaid covers what benefits and protections may be available locally.
How Has the Undocumented Population Changed in 2025?
After growing at a record pace through early 2024, the unauthorized immigrant population began to slow and then decline. Growth slowed considerably in the second half of 2024 after policy decisions under both the Biden and Trump administrations changed how asylum applications and parole programs were handled at the border. The Global Statistics
By May 2025, preliminary estimates suggested the illegal immigrant population had fallen by approximately one million since the start of the year, with researchers noting that the decline may reflect both actual departures and a greater reluctance among immigrants to participate in surveys given the increased enforcement environment. Pew Research Center
Key factors driving the 2025 decline include:
- Significantly reduced southwest border apprehensions, with monthly crossing numbers falling to levels not seen since the early 2000s
- Expanded deportation operations conducted by ICE throughout the interior of the country
- Rescinded deportation protections for several hundred thousand individuals from Cuba, Haiti, Nicaragua, Venezuela, and other nations
- Expired Temporary Protected Status designations affecting hundreds of thousands of additional individuals who had previously been shielded from removal
What Rights Do Undocumented Immigrants Have in the US?
Regardless of immigration status, undocumented individuals in the United States retain certain legal rights under the Constitution and federal law. According to the Department of Homeland Security, all persons in the United States, regardless of status, have the right to remain silent when questioned by law enforcement, the right to speak with an attorney, and the right to due process in immigration proceedings.
Beyond those baseline protections, undocumented individuals also retain the right to:
- Access emergency medical care regardless of immigration status under federal law
- Enroll their children in public schools under the Supreme Court’s ruling in Plyler v. Doe
- File complaints about workplace violations including wage theft, unsafe conditions, and discrimination
- Pursue civil legal claims in court, including personal injury claims resulting from accidents or negligence by others
That last point is particularly significant. Immigration status does not remove a person’s right to seek compensation for injuries caused by someone else’s negligence. If you have been injured in a car accident, you can search for a “car accident lawyer Houston” to understand your legal rights and options for pursuing a personal injury claim.
Injured in Texas Regardless of Immigration Status? Lakhani and McGrath Can Help
If you or someone you know has been injured in an accident in Texas, immigration status does not prevent you from pursuing a legal compensation claim. At Lakhani & McGrath, we represent injured individuals throughout Houston and Texas regardless of their background or status. Our team understands the unique concerns that undocumented individuals may have when considering legal action, and we handle every case with discretion, professionalism, and a genuine commitment to getting you the compensation you deserve. Contact Lakhani and McGrath today for a free consultation and let us fight for your rights.
