How many crimes are committed by illegal immigrants
Executive summary
The best available, peer-reviewed and government-linked analyses indicate that undocumented (illegal) immigrants commit crimes at lower rates than native‑born U.S. citizens, with multiple studies finding substantially lower arrest and conviction rates for violent, drug, and property offenses [1] [2] [3]. However, national estimates are constrained by data gaps—Texas provides uniquely detailed arrest‑status records used in much of the literature—and measures such as arrests or convictions are imperfect proxies that can mask underreporting and law‑enforcement differences [2] [4].
1. What the evidence actually measures: arrests and convictions, not a perfect count of "crimes"
Most rigorous findings rely on arrest and conviction records as proxies for offending because direct measurement of all crimes committed is impossible; the Texas Department of Public Safety data set, used in several influential papers, records immigration status at arrest and shows lower felony arrest rates for undocumented immigrants compared with legal immigrants and U.S.‑born citizens [2] [3]. Researchers and federal summaries explicitly warn that arrests reflect policing practices as well as offending, and that homicide and other rare events can fluctuate more than overall violent crime measures [5] [1] [4].
2. How much lower: magnitudes reported in major studies
A National Institute of Justice summary and the PNAS study using Texas data report that undocumented immigrants were arrested at less than half the rate of native‑born citizens for violent and drug crimes and about one‑quarter the rate for property crimes, while U.S.‑born citizens were more than twice as likely to be arrested for violent crimes and roughly four times as likely for property crimes in the Texas sample [1] [3] [2]. Other analyses, including work cited by NPR and Cato, similarly found substantially lower conviction or incarceration rates among undocumented populations in state‑level studies [6] [7].
3. Consistency across studies — and why skeptics remain
A growing body of state and national research—Migration Policy Institute, Brennan Center, American Immigration Council—converges on the conclusion that immigration, including undocumented migration, is not associated with increases in violent or property crime and in some cases correlates with declines in crime [8] [9] [10]. Yet critics note key limitations: most national systems do not systematically record immigration status at arrest, leading to reliance on Texas (and some state) data; official stats may undercount crimes in immigrant communities because victims or witnesses avoid reporting to police; and federal enforcement databases highlight “criminal aliens” encountered at the border, a different measure that tallies prior convictions in other jurisdictions [2] [4] [11].
4. Alternative measures and government data: “criminal alien” counts versus population rates
Customs and Border Protection publishes counts of “criminal aliens” encountered by border agents, but those summaries report prior convictions discovered in records checks rather than a population crime rate and thus cannot be directly compared with arrest‑rate studies that compute per‑capita rates [11]. Policymakers and media sometimes conflate those counts with incidence rates among all undocumented residents, which is a category mismatch warning found across federal and advocacy reports [11] [10].
5. The remaining gaps and methodological caveats
Researchers acknowledge that underreporting, differential policing, and mobility of undocumented populations can bias observed rates; the literature repeatedly cautions that arrest data may understate unreported interpersonal violence or alternative dispute resolution within communities, and that Texas‑centric findings may not perfectly generalize nationally despite suggestive corroboration from multiple state and national reviews [4] [2] [12]. Where a claim cannot be tested directly with the provided sources—such as an exact nationwide count of crimes committed by undocumented immigrants in a single recent year—this analysis refrains from asserting one.
6. Bottom line for readers and policymakers
Empirical analyses using the best available datasets show that undocumented immigrants, on average, have lower arrest and conviction rates for violent, drug, and property crimes than U.S.‑born citizens, and there is no robust evidence that undocumented immigration increases violent crime; nevertheless, data limitations, differences in measurement, and potential underreporting mean conclusions should be couched with caution and policy debates should focus on improving data collection and targeted public‑safety responses rather than assuming a general crime surge tied to immigration [1] [2] [9].