Hepatitis C virus (HCV) infection is the most reported bloodborne infection in the United States despite being underreported. An accurate estimate of hepatitis C prevalence can inform public health interventions and resource allocation strategies aimed at reducing the health burden and economic costs caused by hepatitis C in the United States, and is necessary to monitor progress toward the global goal of eliminating viral hepatitis as a public health problem by 2030. The most recently available national HCV prevalence estimate in the United States is based on data from 2013–2016. This project will generate an updated estimate of HCV prevalence among the adult (?18 years) US noninstitutionalized civilian population using data from the National Health and Nutrition Examination Survey (NHANES) and compute additional prevalence estimates for populations that are not part of the NHANES sampling frame (e.g., incarcerated people, unsheltered homeless people, active-duty military personnel, and nursing home residents).