How many estimated unauthorized immigrants were added to U.S. population during 2016-2020 under DHS estimates?
Executive summary
DHS’s official residual-method estimates show the unauthorized resident population was essentially flat or declining through 2016–2020, with DHS reporting about 11.4 million in January 2018 and roughly 11.0–11.4 million across those years — not a large net addition like some public narratives imply [1] [2] [3]. Available DHS publications and OHSS tables provide year-by-year estimates and show small year-to-year changes rather than a multi-million jump in 2016–2020 [2] [4].
1. DHS used a “residual” model; that matters for interpreting changes
DHS’s Office of Homeland Security Statistics (OHSS) produces estimates by comparing survey counts of noncitizens to administrative records of lawful residents, a residual approach that converts flows (entries, overstays, removals) into a stock estimate; this method tends to produce stable, incremental year-to-year differences rather than large sudden jumps [4] [2]. That modeling choice means reported changes from 2016 to 2020 reflect assumptions about undercount, emigration, mortality and adjustment to legal status embedded in DHS’s methodology [2].
2. The headline numbers DHS reported for the period: small net changes, not a big surge
DHS’s residual estimates centered around roughly 11 million unauthorized residents in the late 2010s — for example, DHS reported about 11.4 million as of January 2018 and its time series documents estimates across 1990–2022 that show only modest annual variation in 2016–2020 rather than a multi‑million increase over that four‑year span [1] [4]. The OHSS/DHS publications and data tables for the period are the authoritative DHS sources for those year-by-year counts [4] [3].
3. Why other groups report different trends: methodology and data choices
Independent groups (Pew, CMS, MPI, CIS) produce their own estimates using similar residual frameworks but with different assumptions about undercount rates, emigration, and how to treat 2020 ACS anomalies; those methodological differences explain why some organizations show declines or small increases while DHS’s series is comparatively stable for 2016–2020 [2] [1] [5]. For example, DHS assumes specific undercount adjustments and emigration rates that can produce a different trajectory than Pew or center-specific estimates [2] [1].
4. Border flows versus resident-stock estimates: different things entirely
Public attention often focuses on border encounters and modeled illegal entries (apprehensions, successful evaders), which are flow measures and can spike in a year; DHS’s unauthorized population estimates are a stock—how many unauthorized residents are present at a point in time—and flows only translate to stock changes after accounting for removals, deaths, legalizations and emigration [6] [4]. Therefore counting encounters or estimated successful crossings in 2016–2020 does not automatically equate to a commensurate jump in the resident unauthorized population according to DHS’s residual estimates [6] [4].
5. Visa overstays have been an important component of growth, per DHS and researchers
DHS and researchers highlight that visa overstays account for a substantial share of the unauthorized population and of newly undocumented arrivals in recent years; DHS data and secondary analyses indicate overstays were an increasing share of the unauthorized-population dynamics in the 2010s, which shapes how the resident total evolves more than border apprehensions alone [7] [8] [1].
6. Limitations, uncertainties and the 2020 data caveat
Researchers warn that 2020 ACS data were problematic and that coverage assumptions and emigration estimates accumulate error over time; DHS’s residual model includes explicit coverage-adjustment assumptions that affect the 2016–2020 numbers, and DHS’s OHSS tables document uncertainty and methodological choices that analysts must consider [2] [1]. Available sources do not mention a single DHS figure that says “X million unauthorized immigrants were added during 2016–2020”; DHS instead publishes annual point estimates showing modest net changes [2] [4].
7. Bottom line for your query: DHS does not show a multi‑million addition in 2016–2020
DHS’s published residual estimates and OHSS tables indicate the unauthorized resident population remained around ~11 million in the 2016–2018 window (11.4m in Jan 2018 is cited) and show only modest year‑to‑year variation through 2020 rather than a large addition attributed to 2016–2020; the detailed annual OHSS/DHS tables are the place to get the precise year-by-year numbers [1] [4] [2].
If you want, I can extract the DHS OHSS year-by-year table entries for 2016, 2017, 2018, 2019 and 2020 from the DHS report so you can see the exact point estimates and their reported methodology and caveats [4] [2].