According to the Wisconsin Department of Health Services (DHS), Wisconsin ranked third in the nation in 2019 in the percentage of adults who said they had engaged in binge drinking in the past month (21.9%). The situation is equally alarming when it comes to other forms of substance use disorders. According to DHS, between 2014 and 2020, Wisconsin had 6,845 drug overdose deaths. Most involved opioid overdoses (5,338), but multi-drug overdoses (some of which included opioids) were the second most common cause of deaths in that period (3,101), followed by heroin, cocaine, and methamphetamines. Milwaukee County's Behavioral Health Services (BHS) has led efforts to combat substance use disorders in the county for decades, serving as both a direct service provider and as a coordinator of services provided by dozens of community agencies. BHS' Community Access to Recovery Services (CARS) program manages the division's wide range of integrated mental health and substance abuse services, administering a full array of supportive and recovery-oriented services to more than 10,000 Milwaukee County residents each year. This report provides greater clarity on the substance use disorder (SUD) service provision landscape in the county with an eye toward identifying service gaps and priorities for new investment. Dozens of interviews with officials and staff from BHS, community-based providers that are part of its service network, private health system leaders, and other stakeholders. [The Milwaukee County Behavioral Health Services (BHS) commissioned and underwrote this report. Additional support from Advocate Aurora Health. For the executive summary, see ED624661.]