To guide prevention and intervention efforts, the prevalence and impact of child sexual abuse (CSA) victimization among detained and incarcerated populations requires further examination, particularly with consideration of multi-type maltreatment experiences and sex-based variations. This longitudinal population-based study explores these relationships in an Australian birth cohort comprising all individuals born in Queensland in 1983 and 1984 (n = 82,409; 48.68% female). Data include all notified and substantiated harm(s) from child protection services (0 to 17 years), and sentences to youth detention and/or adult incarceration between ages 10 and 30. Findings indicate greater prevalence of CSA amongst detained/incarcerated individuals compared to the general population but emphasize the impact of cooccurring maltreatment (particularly neglect) on the likelihood of custodial outcomes. Important sex-based differences were noted in the intersection of CSA victimization and detention/incarceration. Findings reinforce the need for trauma-informed practices when working with custodial populations, particularly females, and highlight opportunities for prevention of detention/incarceration in at-risk populations, in line with a broader public health approach to child protection.