Screening and treating correctional populations for HIV and HCV infections is essential to successfully addressing both epidemics in the USA. The prevalence of HIV and HCV infection is high in prisons and jails due to increased rates of incarceration among disproportionately affected groups such as injection drug users. Through a search of the published and grey literature and surveying persons overseeing health programs in prisons, we collected data on efforts to determine prevalence first for HIV and then for HCV. Prevalence of both infections varies geographically and temporally, reflecting epidemics in the community as well as local law enforcement policies. We estimate that seroprevalence of HCV in 2015 for persons in U.S. prisons averaged 18%, over tenfold greater than HIV. For both, transmission and acquisition during incarceration are rare. Screening can identify previously undetected cases: the efficiency of a testing strategy depends on local conditions. Universal opt-out screening of entrants is usually best as conducting risk-based screening has challenges. With HCV, the advent of highly effective regimens makes cure feasible. Treatment within facilities has the potential to reduce HCV incidence and disease burden in the community, especially in difficult-to-reach populations. The extraordinarily high cost of HCV treatment regimens and lack of political will are the main barriers to treatment expansion. Just as community-wide HIV viral suppression has required correctional/community coordination, elimination of HCV infection in the USA will depend on a thoughtful, well-funded effort to manage this disease in populations interacting with the criminal justice system.