BACKGROUND: Immigrant status and citizenship influence health and well-being, yet their associations with DNA methylation (DNAm)-based biomarkers of aging - key predictors of healthspan and lifespan, also known as epigenetic aging - remain underexplored. METHODS: Using a representative sample of 2,336 United States (U.S.) adults from the 1999-2000 and 2001-2002 cycles of the National Health and Nutrition Examination Survey (NHANES), we analyzed cross-sectional associations of immigrant status and U.S. citizenship with seven epigenetic aging biomarkers: HannumAge, HorvathAge, SkinBloodAge, PhenoAge, GrimAge2, DNAm Telomere Length, and DunedinPoAm. RESULTS: After adjusting for demographic factors, immigrants had 2.53-year lower GrimAge2 measures (95%CI: -3.44, -1.63, CONCLUSION: Our results support the paradigm of the immigrant mortality advantage and highlight the potential value of epigenetic age measures in studying socioeconomic and broader factors influencing citizen and immigrant health.