Fact check: What is the most common crime committed by illegal immigrants in US prisons according to 2024 data?

1. What the original claims said — clear, repeated assertions that immigration crimes dominate federal sentences

The submitted analyses uniformly assert that immigration offenses are the most frequent federal crimes for non‑U.S. citizens in 2024, with the United States Sentencing Commission’s Quick Facts and Sourcebook Archive reporting 72.3–72.4% of noncitizen sentences fall under immigration guidelines and that illegal reentry comprises the majority of that category ^{[1] [2] [3]}. The GAO report covering 2018–2023 reaches a similar magnitude, saying about 76% of noncitizen federal convictions had immigration as the most serious offense ^[4]. These claims are precise: they refer to sentenced federal cases and to guideline categories rather than to all arrests, removals, or state prison populations. The data also note demographic patterns within those sentenced for illegal reentry — overwhelmingly male and predominantly Hispanic — and short average custodial sentences ^{[1] [3]}.

2. Why the Sentencing Commission data matters — a focused look at prosecutions that produce prison terms

The United States Sentencing Commission data used in the analyses measures federal sentencing outcomes, not total enforcement contacts. That distinction matters because sentencing records enumerate the primary offense for which a person was convicted and sentenced in federal court; by that metric, immigration offenses dwarf other categories (drug trafficking, fraud, firearms) among non‑citizen federal sentences, with drug trafficking the next largest at roughly 14–17.6% in different summaries ^{[1] [2]}. The Sentencing Commission’s sourcebook also reports concrete counts — for example, 17,336 immigration offense cases in the referenced dataset and that about 72.4% of those involve illegal reentry — plus sentencing outcomes such as an average sentence near 12 months and high rates of prison terms for illegal reentry cases ^[3]. These metrics directly answer “most common crime in prisons” when the universe is federally sentenced non‑U.S. citizens.

3. The GAO’s corroboration and timeframe nuance — three‑quarters across recent years

The Government Accountability Office studied federal incarcerations of noncitizens and concluded that approximately three‑quarters of noncitizens sentenced for a federal crime between FY2018 and FY2023 had an immigration‑related most serious offense, producing a percentage figure around 76% ^[4]. That report corroborates the Sentencing Commission’s picture over a multi‑year span, reinforcing that the pattern is not a single‑year anomaly. The GAO also reports the second most common federal offense category for noncitizens as drug trafficking (about 14%), highlighting the gap between immigration and other offense types ^[4]. The GAO’s analysis underscores that while immigration prosecutions dominate federal sentencing statistics for noncitizens, this reflects prosecutorial and statutory priorities at the federal level rather than the complete criminal behavior profile of all noncitizens in the U.S.

4. ICE removal/arrest figures complicate the narrative — many with criminal histories but different denominators

ICE’s FY2024 Annual Report indicates large numbers of removals and notes that a substantial share of removed individuals had criminal histories, including assaults, sexual assaults, weapons offenses and burglaries (with specific arrest tallies cited), and that hundreds of thousands were removed in FY2024 with tens of thousands having criminal convictions or histories ^{[5] [6]}. Those figures can create the impression that violent or property crimes are “most common” among noncitizens, but they describe a different population and process: ICE administrative removals and enforcement arrests, not federal criminal court convictions and sentences. The ICE data highlight public‑safety concerns and enforcement priorities but do not change the finding that federal sentencing records for noncitizens are dominated by immigration offenses ^{[5] [6]}.

5. Reconciling measurements — why “most common crime” depends on which pool you measure

Answering “most common crime committed by illegal immigrants in U.S. prisons” requires defining the population and dataset. Within federally sentenced non‑U.S. citizens, the clear, recurring finding across Sentencing Commission and GAO analyses is that immigration offenses (mostly illegal reentry) are the most frequent charge leading to sentencing and prison in 2024 and recent years ^{[1] [2] [3] [4]}. If instead one looked at ICE arrests, removals, or the subset of noncitizens with documented criminal histories, violent and property offenses appear prominently, but those counts are not directly comparable to federal sentencing tallies and reflect different enforcement mechanisms and selection criteria ^{[5] [6]}. Policymakers and readers must therefore distinguish between sentencing outcomes and broader immigration enforcement statistics.

6. Bottom line answer and important caveats for interpretation

The most defensible, data‑based answer to the original question is: immigration offenses — specifically illegal reentry — are the most common crimes for which non‑U.S. citizens were sentenced to prison in federal courts in 2024, representing roughly 72–76% of those sentences ^{[1] [2] [3] [4]}. Important caveats: these figures concern federal sentencing records (not state prisons, not all arrests or removals), the illegal‑reentry category typically carries short average sentences, and ICE removal/arrest statistics show many removed individuals possess prior criminal convictions for violent or other offenses — a different but relevant policy data point ^{[3] [5] [6]}.