<h1>Use of federal prisons to house immigration detainees expands detention capacity but raises concerns about treatment and prison strain.</h1> The Bureau of Prisons is housing individuals arrested in current immigration enforcement operations to augment detention capacity, but declined to disclose numbers or facilities. Anonymous sources identified federal facilities in Los Angeles, Miami, and Atlanta as being used. This mirrors earlier arrangements to place immigration detainees in federal prisons and has prompted civil claims alleging mistreatment and FOIA litigation seeking records. The deployment raises operational concerns given existing staffing shortages, infrastructure problems, and documented misconduct and violence within federal prisons.