Prior research examining persons with intellectual disabilities who have committed criminal offenses has focused primarily on correctional populations, or those who reside in secure forensic settings in the United Kingdom and Australia. This study describes 235 persons with intellectual, developmental, and cognitive disabilities who reside in a secure forensic psychiatric hospital in the Midwestern United States. Participants were further divided into groups of persons with pervasive developmental disorders (n = 35), fetal alcohol syndrome (n = 18), traumatic brain injuries (n = 52), or IQ scores falling within the range of moderate (n = 20) or mild (n = 55) mental retardation or borderline intellectual functioning (n = 55). These participants presented with significant histories of childhood maltreatment and adversity, serious psychiatric impairment, criminal histories marked by multiple arrests and serious violent behavior, and frequent histories of institutionalization and out-of-home placement. Their adaptive functioning within the community was characterized by limited histories of normative intimate relationships; sporadic, unskilled employment; and difficulties with maintaining residential and psychiatric stability. Important commonalities and future research needs are discussed. Important differences and similarities between groups are discussed and compared with other available literature.