Inmates confined to correctional institutions are exposed to stressors that induce psychological distress. One factor that may be important for inmate mental health is religion. Accordingly, scholars have examined the role of participation in religious activities on inmate mental health. Yet, the role of the religious concentration of prisons on inmate mental health remains unexamined, in spite of research showing that religious contexts impact adjustment to prison. Using data from the 2004 Survey of Inmates in State and Federal Correctional Facilities, this paper presents a multilevel analysis of mental health and religion. The results indicated a mostly positive yet slightly inconsistent relationship between individual religious practice and mental distress. Findings regarding the religious context of prisons indicated a curvilinear relationship whereby inmates in highly religious and highly nonreligious prisons were less likely to report mental distress, while inmates in facilities more evenly mixed between religious and irreligious inmates were most likely to report distress. These findings yield insight into the operation of religion within total institutions.