Vice President J.D. Vance claimed last week that 20 million illegal immigrants entered the U.S. during former President Joe Biden’s tenure in the White House. “Consider that Joe Biden allowed approximately 20 million illegal aliens into our country,” the vice president tweeted. “The American people elected the Trump administration to solve this problem.”
Months earlier, in July 2024—less than two weeks after President Donald Trump selected Vance to be his running mate—the then-senator leveled a similar claim against the Biden administration. “Kamala Harris calls me and Donald Trump disloyal to America,” Vance tweeted. “Call me crazy, but I think it’s disloyal to let in 20 million illegal aliens and poison our citizens with fentanyl.”
Vance has also cited the 20 million figure to refer to the total number of illegal immigrants residing in the U.S., not merely those who entered during the Biden presidency. In June 2024—before he was tapped as Trump’s running mate—Vance cited the 20 million figure, referring to the total U.S. illegal immigrant population that needs housing. “Not having 20 million illegal aliens who need to be housed (often at public expense),” Vance tweeted, “will absolutely make housing more affordable for American citizens.” In October 2024, Vance had also referred to the current illegal immigrant population in the U.S. “We’ve got 20, 25 million illegal aliens who are here in the country,” he said.
On at least two recent occasions—in a March 10 speech and an April 1 tweet—Vance again cited the 20 million figure as the total illegal immigrant population in the U.S.
Vance’s claim not only overstates the number of undocumented immigrants that entered the U.S. during the Biden tenure, but the 20 million figure is higher than the total number of people living in the United States illegally.
Because the illegal immigrant population is, by definition, undocumented, there are no official records to track each illegal entry in the U.S. However, various sources estimate these figures based on available data from the Department of Homeland Security and the Census Bureau’s Current Population Survey (CPS).
A July 2024 report from the Congressional Budget Office (CBO) projected that between fiscal years 2021 and 2024, the number of individuals designated as “other foreign nationals” grew by 7.3 million. According to the report, “other foreign nationals” include “people who entered the United States illegally, people who entered legally in a temporary status and then remained after that legal status expired, and people who were permitted to enter despite not being admissible.” While this category shares a sizable overlap with the illegal immigrant population, there are a few key distinctions between the two groups.
Notably, the CBO’s estimate “includes some legal parolees,” Daniel Di Martino, a Manhattan Institute fellow specializing in immigration policy told The Dispatch Fact Check. These are individuals who have not been awarded temporary legal residency, such as a green card or refugee status, but are not immediately removed because they requested parole based on “urgent humanitarian reasons or a significant public benefit,” according to U.S. Citizenship and Immigration Services. Furthermore, some migrants—such as asylum applicants—who are awaiting immigration court proceedings are similarly counted in the CBO estimate because, like parolees, they were not admitted to the country under a federal immigration program. However, even including these populations, the 7.3 million estimation falls far below the 20 million Vance claimed. The CBO’s estimate falls on the higher end of the spectrum, at least in part because it does “not reflect assumptions about specific policies or predictions about migration patterns,” such as stricter border control policies and more rigid enforcement.
Similarly, the Center for Immigration Studies (CIS), a right-of-center immigration policy think-tank, estimated that 5.4 million illegal immigrants entered the country during the Biden administration. The CIS estimate, which also includes parolees and asylum applicants, uses a similar method to the CBO: It examines CPS data on the foreign-born share of the U.S. population over time, and estimates how much of that foreign-born population growth is attributable to illegal immigration. Both methods use federal administrative data on legal entries and estimates on outmigration and deaths, subtracting that amount from the marginal increase in the foreign-born population to measure the share who entered the U.S. without legal admission. “Without adjusting for those missed by the survey,” wrote CIS director of research Steven Camarota and demographer Karen Zeigler, “we estimate illegal immigrants accounted for 5.4 million or two-thirds of the 8.3 million growth in the foreign-born population since President Biden took office in January 2021.”
Vance’s office did not return The Dispatch Fact Check’s request for comment, and the Manhattan Institute’s Di Martino said the source of Vance’s 20-million figure was unclear to him.
“The reason many claim it was over 10 million people … is that it is the number of ‘encounters’ at U.S. borders and airports over Biden’s term,” Di Martino said.
But even if Vance was counting nationwide border encounters—which totaled just more than 10.8 million between fiscal years 2021 and 2024, per the U.S. Customs and Border Protection data—that does not mean that 10.8 million people entered the U.S. illegally. “Most of those were returned to their countries,” Di Martino explained, “and many were repeat encounters of the same people.” Border encounters are defined as instances where border patrol officers “encounter” a person who is not legally authorized to be in the U.S., either at a border point-of-entry or once they have already crossed the border, per the Office of Homeland Security Statistics.
Individuals removed under Title 42—a Covid-19 pandemic measure that allowed expulsions under public health premises, and in effect from March 2020 to May 2023—were also counted toward border encounters. So, for example, if a person was initially expelled from the country under Title 42, and later returned at the U.S. border seeking reentry despite not being eligible for legal or refugee status, those interactions would be recorded as two separate border encounters. And, if that same person later reenters the U.S. unlawfully and is apprehended by border control, that would count as a third separate encounter.
Vance’s claims that the entire illegal immigrant population in the U.S. is 20 million also doesn’t hold up. CIS calculated that, as of January 2025, there were 15.4 million illegal immigrants residing in the U.S. Similarly, Pew Research, which calculates the illegal immigrant population using the Census Bureau’s annual American Community Survey, unlike CIS—estimated a total of 11 million unauthorized migrants in the U.S. in 2022.
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