Foreign-Born Population Present in Every Congressional District

Why It Matters

The United States had an estimated 50.2 million foreign-born residents as of 2024, roughly 14.8 percent of the national population, and they live in every single one of the 435 congressional districts. That means immigration policy, whatever form it takes, has direct constituency consequences for virtually every member of Congress, regardless of party or geography. A new Congressional Research Service report offers a granular look at the foreign-born population by state and congressional district, and the picture it paints complicates the political calculus for everyone.

The Big Picture

Foreign-Born Population by State: The Scale of the Data

The report, authored by CRS research librarians Tilly Finnegan-Kennel and Ben Leubsdorf, draws on the U.S. Census Bureau's American Community Survey (ACS), using one-year estimates for 2024. The foreign-born population statistics cover all 50 states, the District of Columbia, Puerto Rico, and all 435 congressional districts as configured in the 119th Congress.

The concentration of foreign-born residents by district is striking. Florida's 26th Congressional District reported that 56.1 percent of its residents were born outside the United States, the highest share in the country. New York's 6th Congressional District came in at 55.4 percent. Florida's 27th District reached 54.3 percent, and California's 17th District came in at 50.9 percent. In each of these districts, more than half of all residents were born in another country.

At the state level, California reported the largest raw number, with an estimated 10.9 million foreign-born residents, representing 27.6 percent of the state's total population. Texas followed with 5.76 million, or 18.4 percent. Florida reported 5.39 million, or 23.1 percent. New York came in at 4.62 million, or 23.3 percent. New Jersey, at 25 percent, rounded out the top five by share of total population.

At the other end of the spectrum, Montana and West Virginia each reported foreign-born populations representing just 2.1 percent of their total populations.

Foreign-Born Population Statistics and the Unauthorized Immigrant Question

One of the report's most consequential disclosures points out that the Census Bureau does not collect or publish data on whether a resident is authorized to be in the United States. The ACS questionnaire asks where a person was born and whether they are a citizen, but it does not ask about immigration status. That means the 50.2 million figure encompasses naturalized citizens, green card holders, temporary visa holders, and people illegally present in the country, with no breakdown between those categories.

For estimates of the unauthorized population specifically, the report compiles figures from multiple sources and the range is wide. The Department of Homeland Security, using data through January 2022, estimated 11 million unauthorized immigrants. The Pew Research Center put the figure at 14 million for 2023. The Center for Immigration Studies estimated 14.2 million as of 2025. The Migration Policy Institute estimated 13.7 million for 2023, and the Center for Migration Studies of New York put the figure at 12.2 million for 2023.

That spread of more than 3 million people, depending on the source and methodology, reflects both the inherent difficulty of counting a population that does not self-identify in surveys, and the differing methodological assumptions each organization brings to the task.

Political Stakes

Congressional District Immigration Data and the Apportionment Fight

The report's data feeds directly into one of the most consequential governance debates of the current moment, namely who gets counted for the purposes of apportioning congressional seats.

The Trump administration has moved to exclude unauthorized immigrants from apportionment counts following the 2030 Census, a position that would represent a break from historical practice. Because apportionment has always been based on total persons, not citizens or authorized residents, states with large foreign-born populations stand to lose House seats if that practice changes. California, Texas, Florida, and New York, the four states with the largest foreign-born populations, would be most directly affected.

Republican senators have introduced legislation aimed at codifying the exclusion of unauthorized immigrants from apportionment counts for both the Electoral College and congressional district boundaries. If the foreign-born population in states like California and New York were partially excluded from the population base used for apportionment, those states could lose representation, shifting political power toward states with smaller immigrant populations, many of which lean Republican.

For Democrats, the data cuts both ways. The congressional districts with the highest concentrations of foreign-born residents are largely Democratic-held seats in South Florida, the New York metro area, and California. Those members have the most direct political incentive to oppose apportionment changes. But Democrats in competitive districts in states like Georgia, North Carolina, and Arizona, where the foreign-born population has grown but remains a smaller share of the total, face a more complicated calculation.

What It Means for the Administration

The administration's mass deportation agenda runs into a data problem that this report makes explicit. Because federal surveys do not track immigration status, enforcement agencies cannot use Census or ACS data to identify or locate unauthorized immigrants. The gap between DHS's own 2022 estimate of 11 million and the more recent third-party estimates of 13.7 to 14.2 million also suggests the unauthorized population may have grown substantially, complicating resource planning for large-scale enforcement operations.

The report also references a Congressional Budget Office analysis, published in June 2025, examining the effects of immigration on state and local budgets. That analysis is relevant to the administration's ongoing pressure campaign against sanctuary jurisdictions and debates over whether federal funding should be conditioned on immigration enforcement cooperation.

The Bottom Line

Two things stand out from this report. First, the scale: nearly one in seven U.S. residents is foreign-born, a figure that spans every congressional district in the country. There is no member of Congress whose constituents are untouched by immigration policy, whatever their district's specific demographics look like.

Second, the data gap: the most politically charged question, how many unauthorized immigrants are in the United States and where do they live, cannot be answered by the federal government's own official data. The Census Bureau's surveys are not designed to capture immigration status, and the estimates that do exist vary by millions, depending on the source. That gap matters enormously for policy, because enforcement decisions, resource allocation, and apportionment debates are all being made against a backdrop of genuine statistical uncertainty.

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