Conditions in immigrant detention centers facilitate the spread of infectious diseases like COVID-19. However, there is no publicly-available data on detainees’ health characteristics, making it difficult to estimate the prevalence of risk among detained people. We use cross-sectional survey data from the only survey of detained immigrants, conducted in California in 2013–2014, to assess the prevalence and health-related correlates of health conditions among detained immigrants. We calculated the proportion of detained immigrants with chronic conditions, their interruptions in care, and stratified by sociodemographic characteristics, evaluating differences using two-tailed tests. Among 529 detained immigrants, 42.5% had at least one chronic health condition; 15.5% had multiple chronic conditions. 20.9% experienced disruption in care upon entering detention. 95.6% had access to stable housing in the U.S. Many detained people face health conditions that confer greater risk for poor outcomes with COVID-19. Stable residence can facilitate release of detainees via Alternatives to Detention programs.