BackgroundAlthough preventable, adverse childhood experiences (ACEs) can result in lifelong health harms. Current surveillance data on adults’ exposure to ACEs are either unavailable or incomplete for many U.S. states.MethodsCurrent estimates of the proportion of U.S. adults with past ACEs exposures were obtained by analysing individual-level data from 2019 to 2020 Behavioural Risk Factor Surveillance System―annual nationally representative survey of noninstitutionalized adults aged 18+years. Standardised questions measuring ACEs exposures (presence of household member with mental illness, substance abuse, or incarceration; parental separation; witnessing intimate partner violence; experiencing physical, emotional, or sexual abuse during childhood) were categorised into 0, 1, 2–3, or 4+ACEs and reported by sociodemographic group in each state. Missing ACEs responses (state did not offer ACEs questions or offered to only some respondents; respondent skipped questions) were modelled through multilevel mixed-effects logistic (MMEL) and jackknifed MMEL regressions.ResultsIn 2019–2020, an estimated 62.8% of U.S. adults had past exposure to 1+ACEs (range: 54.9% in Connecticut; 72.5% in Maine), including 22.4% of adults who were exposed to 4+ACEs (range: 11.9% in Connecticut; 32.8% in Nevada). At the national and state levels, exposure to 4+ACEs was highest among adults aged 18–34 years, those who did not graduate from high school, or adults who did not have a healthcare provider. Racial/ethnic distribution of adults exposed to 4+ACEs varied by age and state.ConclusionsACEs are common but not equally distributed. ACEs exposures estimated by state and sociodemographic group can help decisionmakers focus public health interventions on populations disproportionately impacted in their area.