The United States opioid epidemic claims the lives of tens of thousands of Americans each year due to opioid overdose. Hospital emergency departments (EDs) have been essential in combatting the crisis by stabilizing patients who are experiencing an overdose and other symptoms of their opioid use disorders (OUD). Over time, EDs have also become more involved in providing other addiction treatment services, such as prescribing and administering medications for opioid use disorder (MOUD) and referring their patients to outpatient behavioral health care providers for follow-up treatment. Policymakers have been essential in driving EDs to expand the scope of their addiction medicine services and referrals by creating specialized programs that provide incentivizes to participating hospitals.The following report summarizes advances in opioid use disorder care within EDs in 19 hospitals across 8 health systems in Michigan. These hospitals participated in an initiative created by the Community Foundation for Southeast Michigan (CFSEM) in collaboration with the Michigan Opioid Partnership (MOP), a public-private collaborative with a mission to reduce opioid overdoses in Michigan by improving the access and quality of prevention, treatment, harm reduction, and recovery services. The initiative was supported by State Opioid Response grants from the Michigan Department of Health and Human Services. Vital Strategies, a global public health organization that helps governments strengthen public health, provided support, technical assistance, and resources to improve hospital coordination and designed the evaluation. Specifically, hospitals were provided funding by CFSEM to improve OUD care training, coordination, delivery, and quality in their EDs. Hospitals and health systems funded by CFSEM included the University of Michigan Health System (Michigan Medicine hospital), Trinity Health (Mercy Health Muskegon, Mercy Health St. Mary, St. Joseph Mercy - Ann Arbor, St. Joseph Mercy Chelsea, St. Joseph Mercy Livingston, St. Joseph Mercy Oakland), Henry Ford Health Systems (Henry Ford – Main, Henry Ford - Wynadotte/ Brownstown), Beaumont Health Systems (Beaumont - Royal Oak, Beaumont – Troy, Beaumont – Wayne), Ascension (Ascension St. John Hospital, Ascension Genesys Hospital), Munson Healthcare (Munson Medical Center - Traverse City, Sparrow Health System (Sparrow Hospital - Lansing), Spectrum Health (Spectrum Health Butterworth), War Memorial, and Hurley Medical Center. After receiving funding, hospitals created work plans related to improving opioid use disorder care in their EDs, including by increasing their number of employed X-waivered providers, integrating clinical tracking and support tools into electronic medical records, and connecting patients with behavioral health care providers in the community to establish treatment continuity (i.e., "warm handoffs"). Researchers with the Bloomberg Overdose Prevention Initiative at the Johns Hopkins Bloomberg School of Public Health evaluated hospital improvement in these areas using surveys and qualitative interviews with participants