The Pittsburgh environmental movement community consists of affiliates of state, national, and international organizations as well as free-standing local organizations. These groups address long-standing problems such as air and water pollution as well as more recent concerns about fracking, environmental justice, and climate change. In this chapter, I describe my sampling of the grassroots environmental movement in Pittsburgh. For the five groups that I studied intensively, I provide narratives of their origins and major activities as well as a brief description of their organizational structures and ideological approaches in this chapter (see also Staggenborg 2018; Staggenborg and Ogrodnik 2015). In subsequent chapters, I draw on these cases to look more closely at processes of mobilization, including internal organizational dynamics and strategic decision-making.