Large urban jails have become a collection point for many persons with severe mental illness. Connections between jail and community mental health services are needed to assure in-jail care and to promote successful community living following release. This paper addresses this issue for 2855 individuals with severe mental illness who received community mental health services prior to jail detention in King County (Seattle), Washington over a 5-year time period using a unique linked administrative data source. Logistic regression was used to determine the probability that a detainee with severe mental illness received mental health services while in jail as a function of demographic and clinical characteristics. Overall, 70 % of persons with severe mental illness did receive in-jail mental health treatment. Small, but statistically significant sex and race differences were observed in who received treatment in the jail psychiatric unit or from the jail infirmary. Findings confirm the jail's central role in mental health treatment and emphasize the need for greater information sharing and collaboration with community mental health agencies to minimize jail use and to facilitate successful community reentry for detainees with severe mental illness.