Numerous policy issues surround the incarceration of religious extremists and individuals with terrorist ties. These inmates must be managed, prevented from precipitating security risks, and stopped from recruiting or encouraging others to commit terrorist acts. To systematically investigate the prevalence of these issues in U.S. prisons, the authors conducted a survey of wardens of state-level maximum security prisons in the United States. Results suggest that the majority of facilities currently have existing security threat groups (STGs) with extremist religious beliefs. Large majorities of wardens indicated shortages of religious service providers, with nearly all allowing volunteers to supplement existing religious services. A multinomial logistic regression model suggests that (in accordance with previous literature on gangs) wardens pursuing policies of isolating these prisoners believe these policies to be much more effective than other strategies, such as increased monitoring. Additionally, more frequent staff training relevant to managing these individuals is significantly related to wardens' judgments that their policies are effective. Abstract published by arrangement with Sage Journals.