This dissertation examines the development of grassroots environmental organizations between 1970 and 2000 and the role they played in the larger American environmental movement and civil society during that period. Much has been written about growth in environmental values in the United States during the twentieth century and about the role of national environmental organizations in helping to pass landmark federal-level environmental laws during the 1960s and 1970s. This study illuminates a different story of how citizen activists worked to protect and improve the air, water, healthfulness and quality of life of where they lived. At the local level, activists looked much different than they did in Washington, D.C.--they tended to be volunteers without any formal training in environmental science or policy. They were also more likely to be women than at the national level. They tended to frame environmental issues and solutions in familiar ways that made sense to them. Rather than focusing on the science or economics of an environmental issue, they framed it in terms of fairness and justice and giving citizens a say in the decisions that affected their health and quality of life. And, as the regulatory, political, and social landscape changed around them, they adapted their strategies in their efforts to continue to affect environmental decision making. Over time, they often connected their local interests and issues with more sophisticated, globalized understandings of the economic and political systems that under laid environmental issues. This study examines three case studies in the rural Great Plains, urban Southwest, and small-town Appalachia between 1970 and 2000 in an attempt to understand community-based environmental activism in the late twentieth century, how it related to the national environmental movement, the strategies local-level groups employed and when and why, the role of liberal democratic arguments in their work and in group identity formation, the limits of those arguments, and how the groups, their strategies, and the activists themselves changed overtime. These three groups were the Northern Plains Resource Council in Montana, Southwest Environmental Service in Southern Arizona, and Save Our Cumberland Mountains in Eastern Tennessee.