After reviewing the policy debate on the use of restricted housing units for inmates who engage in misconduct in the general inmate population, this article argues that advocates who want RHUs closed must recognize the danger faced by mentally ill inmates in the general inmate population, where they can be victimized and manipulated. Alternative housing units for mentally ill inmates can provide a safer environment and enable specialized programming matched to their treatment needs. In the case of Allegheny County, inmates diagnosed as mentally ill are placed in a diversionary treatment unit (DTU). DTUs are secure units where the inmates are offered a minimum of 20 hours out-of-cell activity per week. Of these hours, a minimum of 10 hours are structured (staff facilitated) and a minimum of 10 are unstructured (yard/dayroom). Inmates in the DTU are reviewed weekly by administrative and treatment staff. Inmates who are seriously mentally ill and who also develop a history of maladaptive or assault behavior may be referred to a SRTU (secure residential treatment unit). This is a longer termed phase program for those individuals who show an increased need for security and for mental health services because of their serious mental illness.