What are the official estimates of net illegal immigration during 2021–2025?

1. The official headline numbers: CBO’s year‑by‑year view

The Congressional Budget Office’s demographic update characterizes the 2021–2024 period as a dramatic influx—reporting net immigration of about 830,000 in 2021, 2.0 million in 2022, 2.4 million in 2023 and 1.8 million in 2024—and then revising its outlook sharply downward for 2025 by projecting net immigration of −290,000 in the “other foreign nationals” category and warning that net immigration will be smaller from 2025 to 2033 than previously thought ^[1].

2. Census Bureau and DHS signals: big mid‑year totals and methodological shifts

The Census Bureau’s releases—working in part from DHS administrative records—estimated total net immigration for July 2023–June 2024 at about 2.8 million, a figure that reflects releases and paroles as well as apprehensions and which underpinned Pew and other population‑estimate revisions; the Census changes to methodology for 2021–24 altered how net international migration was measured and contributed to upward revisions of unauthorized‑population estimates for 2022–2024 ^{[2] [4]}.

3. Monthly dynamics and the crash in net unauthorized inflows by 2025

High‑frequency work using DHS and ICE administrative flows finds a surge in 2021–2023 and then a rapid decline: one Dallas Fed reconstruction shows net unauthorized immigration peaking in late 2023 and falling sharply in 2024, with monthly net unauthorized immigration down from around 105,000 in December 2024 to about 19,000 by March 2025—a roughly 82 percent drop—and projects much lower or even negative net flows into 2025 depending on enforcement and removals assumptions ^[3].

4. Why official and independent estimates diverge: data, definitions and policy shocks

Part of the disagreement stems from different definitions (total net foreign‑born immigration versus “unauthorized” specifically), timing windows, and reliance on administrative encounter data versus household surveys; CBO and Census combine multiple sources including DHS parole and release figures, while survey‑based series (CPS) and independent analysts point to undercounts, methodological changes, and the large policy shifts of 2024–2025—parole programs, asylum restrictions and stepped‑up removals—that make short‑run estimates volatile and contested ^{[1] [2] [4]}.

5. Alternative tallies and political contestation over the totals

Non‑governmental groups produce very different totals: advocacy or restriction‑oriented organizations such as FAIR and CIS have published much higher estimates of the unauthorized population and of cumulative net illegal inflow since 2021 (claims of millions more), arguing that survey undercounts and lagging official tallies miss large populations; those estimates point to deep political motives and different methodological choices that widen the gap with CBO/Census figures ^{[5] [6] [7]}.

6. Bottom line and caveats

The most defensible “official” picture is mixed: CBO and Census‑DHS‑informed estimates show very large net inflows in 2021–2024 (hundreds of thousands to low millions per year) and then a marked reversal or collapse by 2025—with CBO projecting −290,000 in a major category for 2025 and DHS/Census‑based series and independent reconstructions showing steep declines to near‑zero or net outflow by early 2025—while alternative private estimates claim substantially larger cumulative net illegal immigration across 2021–2025 ^{[1] [2] [3] [5]}. Reporting limits: available sources do not produce a single agreed, audited annual “net illegal immigration” figure for every calendar year 2021–2025, and methodology differences explain much of the divergence ^[4].