How many undocumented immigrants file federal tax returns using ITINs each year and how has that trended since 2010?

1. What the headline numbers say: ITIN returns and active ITINs

Contemporary reporting and IRS summaries provide three related but distinct measures: the number of federal tax returns filed using an ITIN in a given year, the number of active ITINs on the IRS rolls, and the cumulative ITINs ever issued; public sources cite “over 3 million” ITIN-filed returns in 2010 (Bipartisan Policy Center), about 4.4 million ITIN filers referenced in a mid‑2010s IRS snapshot (American Immigration Council), and “more than 2.5 million” federal tax returns filed by ITIN filers in 2019 according to IRS figures reported by CNN and the Tax Policy Center, while audits and reporting show roughly 5.4 million active ITINs in January 2021 and more than 5.8 million active ITINs at the end of 2022 ^{[1] [2] [3] [4] [5]}.

2. How “ITIN filers” maps (imperfectly) to undocumented filers

Experts and advocacy groups consistently warn that ITIN holders are a mixed population: many are undocumented immigrants, but ITINs are also issued to nonresident aliens, certain visa holders, spouses and dependents of lawful residents, and others who lack SSNs, so ITIN counts do not equal counts of undocumented filers one‑for‑one ^{[2] [6]}. Multiple analyses nonetheless treat ITIN filing as the best available proxy for undocumented tax filing behavior because “the overwhelming majority” of ITIN filers are believed to be undocumented, a judgment repeated in ITEP, the American Immigration Council, and other reports ^{[7] [2] [4]}.

3. Trend since 2010: rise, fluctuation, and measurement shifts

The pattern since 2010 is not a simple monotonic trend; sources indicate a high point in ITIN-filed returns around or above 3 million in 2010, a larger ITIN filer figure reported mid‑decade (4.4 million reported for a past year), and a lower count of roughly 2.5 million ITIN-filed returns documented for 2019—suggesting fluctuation driven by enforcement, outreach, economic conditions, and changing tax rules—while the stock of active ITINs continued to rise into the early 2020s ^{[1] [2] [3] [4] [5]}. Analysts also note administrative factors that affect year‑to‑year counts: the IRS issues and retires ITINs, accounts expire if unused for three years, and law changes (for example, restrictions on refundable child tax credit eligibility) alter incentives to file with ITINs ^{[8] [1]}.

4. How to interpret these numbers—and where uncertainty remains

Quantitative estimates that translate ITIN usage into a share of the undocumented population vary widely: some studies and advocates estimate that at least half of undocumented households file income tax returns using ITINs, while ITEP and others emphasize that many undocumented workers pay taxes through withholding without ever filing returns ^{[9] [10]}. Because the IRS does not publish an official annual tally of “undocumented” filers and ITINs serve multiple legal populations, any claim equating ITIN returns directly to undocumented filers must be couched in uncertainty; the sources used here are explicit about that limitation ^{[2] [4]}.

5. Bottom line for the record and policy context

Measured by IRS‑reported ITIN returns, the landscape shows millions of ITIN‑filed returns each year—over 3 million around 2010, higher mid‑decade counts cited (about 4.4 million in some snapshots), and about 2.5 million ITIN‑filed returns in 2019—while the number of active ITINs on IRS rolls rose into the 5–6 million range by 2021–2022, but none of these figures provide a precise annual headcount of undocumented immigrants filing taxes because ITIN holders include other noncitizen groups and because filing incentives and administrative rules have changed over time ^{[1] [2] [3] [4] [5] [8]}.