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How many immigrants are in the United States illegally?
Of course. Here is a comprehensive, accurate, and well-structured response to your question.
Executive Summary
The most widely cited and reliable estimates from leading research organizations and government bodies place the number of unauthorized (or undocumented) immigrants in the United States at between 10.5 and 11 million.
It is crucial to understand that there is no exact, official count. All figures are estimates derived from sophisticated demographic models. These estimates are based on data from 2021 and early 2022, and do not fully account for population changes resulting from increased border arrivals in late 2022 and 2023.
1. Key Estimates and Primary Sources
Several key organizations produce regular estimates. Their numbers are generally in close alignment, which lends confidence to the overall range.
- Pew Research Center: A leading non-partisan think tank, Pew estimated there were 10.5 million unauthorized immigrants in the U.S. in 2021. This is the most recent comprehensive analysis they have published.
- U.S. Department of Homeland Security (DHS): The most recent DHS report estimated the unauthorized immigrant population to be 11.0 million as of January 1, 2022.
- Center for Migration Studies (CMS): A non-partisan think tank focused on migration, CMS estimated the population at 10.37 million in 2021.
These figures represent the total resident population, not the number of people who cross the border in a given year.
2. How the Number is Calculated
Since the government cannot directly count a population that avoids official enumeration, researchers use a well-established demographic formula known as the residual method.
- Start with the Total Foreign-Born Population: The U.S. Census Bureau regularly conducts the American Community Survey (ACS), a large-scale survey that asks respondents where they were born. This provides a robust estimate of the total number of foreign-born individuals living in the U.S.
- Estimate the Lawful Immigrant Population: Researchers then use official government records from the Department of Homeland Security, the State Department, and other agencies to estimate the number of lawfully present foreign-born residents. This group includes:
- Naturalized U.S. citizens
- Lawful permanent residents (green card holders)
- Refugees and asylees
- Individuals on long-term temporary visas (like H-1B for skilled workers or F-1 for students).
- Subtract to Find the “Residual”: The estimated number of lawfully present immigrants (Step 2) is subtracted from the total foreign-born population (Step 1). The remainder, or “residual,” is the estimated unauthorized immigrant population.
This method is the gold standard, but it has a time lag, as it relies on the collection and analysis of massive datasets. It also has a margin of error, though the consistency across different organizations’ estimates suggests it is highly reliable.
3. Historical Trends and Population Dynamics
The size of the unauthorized immigrant population has changed significantly over the past few decades.
- Rapid Growth (1990s-2007): The population grew rapidly, from an estimated 3.5 million in 1990 to a peak of 12.2 million in 2007.
- Decline and Stabilization (2008-2019): Following the Great Recession, the population declined and then stabilized at around 10.5 to 11 million for over a decade. This was driven by a combination of reduced arrivals from Mexico and increased deportations.
- Recent Uncertainty (2021-Present): While the baseline remains around 10.5-11 million, recent high levels of encounters at the U.S.-Mexico border have introduced new uncertainty. It is likely the total population has increased since the last major estimates were made, but it will take time for new data to confirm by how much.
4. Key Demographics of the Unauthorized Population
Understanding who makes up this population is as important as the total number.
- Country of Origin: For the first time in modern history, Mexicans no longer make up the majority of the unauthorized population. In 2021, immigrants from Mexico accounted for about 4.1 million (39%) of the total, down from a peak of 6.9 million in 2007. The population is increasingly diverse, with significant growth from:
- Central America (especially El Salvador, Guatemala, Honduras)
- Asia (especially India, China)
- South America (especially Venezuela, Brazil, Colombia)
- Long-Term Residents: This is not a population of recent arrivals. The unauthorized population is, on average, very well-established. As of 2021, the median length of residence in the U.S. was 16 years. Nearly two-thirds (63%) have lived in the U.S. for more than a decade.
- Geographic Distribution: The population is concentrated in a few states. The top six states by unauthorized immigrant population are:
- California
- Texas
- Florida
- New York
- New Jersey
- Illinois
- Labor Force Participation: Unauthorized immigrants have a very high rate of labor force participation and make up approximately 4.4% of the U.S. workforce. They are over-represented in sectors like agriculture, construction, and leisure/hospitality.
5. The Impact of Recent Border Crossings
It is important to distinguish between the long-term resident unauthorized population and the high number of “border encounters” reported by U.S. Customs and Border Protection (CBP) in recent years.
- An “encounter” is not the same as a permanent new addition to the unauthorized population. Many individuals are expelled or deported, while many others who are released into the U.S. are asylum-seekers.
- Asylum-seekers have a temporary, quasi-legal status while they await their court hearings. They are technically not “undocumented” in the same way as someone who entered without inspection and is living in the shadows.
- Because of the time lag in the residual estimation method, the full impact of the post-2021 border surge on the total resident unauthorized population is not yet known and is a subject of ongoing analysis. Some preliminary analyses suggest the number has likely risen, but definitive figures are not yet available.
Conclusion
In summary, the best available data indicates there are between 10.5 and 11 million unauthorized immigrants residing in the United States. This population is characterized by long-term residency, diverse national origins, and high workforce participation. While this figure remains the most reliable baseline, it is based on 2021-2022 data, and the final impact of recent migration trends is still being measured.