The Patient Protection and Affordable Care Act (ACA), the health reform law passed by the Obama administration and Congress in 2010, will have vast implications for the provision of health services to incarcerated individuals, including expanded access to mental health and substance abuse treatment. An underappreciated impact of California’s AB 109 adult corrections realignment is that county jails are now the primary providers of medical care for long-term realigned inmates. The Community Oriented Correctional Health Services (COCHS) agency, a sixteen year effort funded by the Robert Woods Johnson Foundation, has argued that with 12 million people passing through the country’s jails every year, local correctional agencies are uniquely positioned to improve public health and reduce recidivism. One of their recent national studies, provides a thorough overview of both the opportunities and challenges facing local jurisdictions with the full implementation of the Affordable Care Act in 2014. Their researchers note that as many as 90% of jail detainees have no private or public health insurance and that these rates are highest in those states that exclude childless adults from Medicaid eligibility. Under the 2010 ACA health reform law, most of these individuals will become eligible for health care coverage in 2014. The COCHS study cites ample research showing that detained or incarcerated individuals have disproportionately higher rates of chronic medical conditions, substance use disorders, serious mental illness, and co-occurring disorders, and these underlying problems regularly contribute to recurring criminal behavior. Treating these problems through expanded access to Medicaid could significantly decrease arrest rates and recidivism rates for those states and counties that are ready and willing to facilitate the expansion of access for their incarcerated population. A new study by the UCLA Center for Health Policy Research found that in California alone, approximately 500,000 currently uninsured adults in need of mental health treatment will be able to access it through the ACA reforms, including Medi-Cal and the California Health Benefit Exchange. The study did not take incarceration status into account.The study notes that many regulations regarding incarcerated populations are still being debated and that states will have significant leeway in determining eligibility. For example, the authors write, “What is yet undetermined is whether and how eligibility distinctions will be made between individuals who are pre-trial and those who are post-sentence, and between those who are acquitted and those who are found guilty.” Considering that California counties will be bearing the fiscal responsibility for providing medical care to the realigned population under AB 109, it is incumbent upon California decision-makers to expand the federally reimbursable Medicaid coverage as broadly as possible. As this study demonstrates, counties would have unprecedented opportunities to establish new in-facility treatment programs by partnering with community providers, or to create re-entry centers that offer primary medical, substance use and mental health care. County-based strategies such as these would make substantial progress in addressing some of the underlying causes of criminogenic behavior, rather than just responding to symptoms with incarceration practices that have already shown to be ineffective and unconscionably expensive.