Mental institutions housed individuals with intellectual and developmental disabilities (I&DD) until the 1960s. Community-based alternatives became the preferred treatment method to relieve overcrowding and declining living conditions. This movement towards deinstitutionalization had several unintended consequences, including placing responsibility on the criminal justice system to serve as mental health providers. This study examines treatment programs for offenders with intellectual and developmental disabilities in county jails and probation and parole offices in Pennsylvania to examine current treatment models. The research examines the extent of programming for individuals with I&DD and provides recommendations for improving service provision for this growing population of offenders.