Childhood maltreatment and involvement with child protective services (CPS) is associated with a variety of negative outcomes, including homelessness. In order to better understand that connection, we used linked administrative records to develop a population-level, epidemiological characterization of the child protection histories of young adults accessing homelessness services in San Francisco County. We found that 1 of every 2 homeless youth had been reported for maltreatment at least once during childhood, yet the prevalence of past CPS involvement varied across groups. Homeless female youth were significantly more likely to have a CPS history than male youth (58.1% vs. 41.5%). Nearly twice as many black clients accessing homelessness services had a CPS history as did white clients (59.8% vs. 31.8%). Roughly half (47.3%) of those with a childhood history of reported maltreatment had been reported for maltreatment in another county in the state. Targeting services that address past trauma and instability among homeless young adults may be justified given the prevalence of CPS history in this population. Check out our project page to access the academic paper and other information about this interesting study.