© 2015 Wolters Kluwer Health. Context: The Patient Protection and Affordable Care Act (ACA) is changing the landscape of health systems across the United States, as well as the functioning of governmental public health departments. As a result, local health departments are reevaluating their roles, objectives, and the services they provide. Objective: We gathered perspectives on the current and future impact of the ACA on governmental public health departments from leaders of local health departments in the Big Cities Health Coalition, which represents some of the largest local health departments in the country. Design: We conducted interviews with 45 public health officials in 16 participating Big Cities Health Coalition departments. We analyzed data reflecting participants' perspectives on potential changes in programs and services, as well as on challenges and opportunities created by the ACA. Results: Respondents uniformly indicated that they expected ACA to have a positive impact on population health. Most participants expected to conduct more population-oriented activities because of the ACA, but there was no consensus about how the ACA would impact the clinical services that their departments could offer. Local health department leaders suggested that the ACA might create a broad range of opportunities that would support public health as a whole, including expanded insurance coverage for the community, greater opportunity to collaborate with Accountable Care Organizations, increased focus on core public health issues, and increased integration with health care and social services. Conclusions: Leaders of some of the largest health departments in the United States uniformly acknowledged that realignments in funding prompted by the ACA are changing the roles that their offices can play in controlling infectious diseases, providing robust maternal and child health services, and more generally providing a social safety net for health care services in their communities. Health departments will continue to need strong leaders to strengthen and maintain their critical role in protecting and promoting the health of the public they serve.