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During 2016-2023, 37 U.S. states experienced hepatitis A outbreaks associated with person-to-person transmission. We sought to describe the epidemiology of the outbreaks and characterise outbreak response efforts over time. We analysed outbreak databases from 37 states, survey responses from 33 states, and hepatitis A case reports from the National Notifiable Diseases Surveillance System for all 50 states and Washington, DC, during August 1, 2016-December 31, 2023. Among 44,930 reported outbreak-associated cases, most occurred among males (62%), non-Hispanic White persons (65%), and those aged 30-49 years (54%); 62% were hospitalised and 1% died. Commonly reported risk factors for HAV infection were drug use (53%) and homelessness or unstable housing (14%). Sixty-seven percent of adults had a documented indication for hepatitis A vaccination. In late 2017, CDC stood up a national incident management system to coordinate communication between outbreak-affected states, facilitate vaccine delivery, and provide technical assistance. States with available data reported administering more than 5.3 million adult hepatitis A vaccines collectively; most states administered vaccines in correctional facilities, local health departments and homeless shelters. Outbreak-associated cases peaked in 2019 and then declined annually. As outbreak response capacity scaled up nationwide, states with later outbreak start dates tended to experience smaller outbreaks than those with earlier start dates. Unprecedented hepatitis A outbreaks were controlled by a robust vaccine response in 37 states. Continued vigilance and providing access to vaccination for recommended populations will be critical to preventing similar outbreaks in the future.