Copyright ©2017 Annual Reviews. Public health practice in the twenty-first century is in a state of significant flux. Several macro trends are impacting the current practice of governmental public health and will likely have effects for many years to come. These macro trends are described as forces of change, which are changes that affect the context in which the community and its public health system operate. This article focuses on seven such forces of change: the Patient Protection and Affordable Care Act, public health agency accreditation, climate change, health in all policies, social media and informatics, demographic transitions, and globalized travel. Following the description of each of these, this article then turns to possible approaches to measuring, tracking, and understanding the impact of these forces of change on public health practice, including the use of evidence-based public health, practice-based research, and policy surveillance.