Whether due to climate change, drought, flooding, competing demands, or pollution, watersheds across the globe are under significant duress. To respond to these complex challenges, collaborative approaches to watershed governance have increasingly been adopted in the United States, but very few studies have yet to systematically assess their true effectiveness. This book addresses a significant gap in research by undertaking a comprehensive study of alternative, collaborative structures and whether these produce better water quality outcomes than traditional regulatory governance. Analyzing almost one quarter of US watersheds and examining both the revealed and perceived outcomes of watershed stakeholder collaboration, it is the first large-scale study on this topic. The insights the chapters provide will equip readers with a nuanced and generalizable understanding of the effectiveness of collaboration in natural resource management, which will be of great interest to researchers and practitioners in wide-ranging environmental and public policy roles.