“The Colorado River travels through seven states and two countries, nine national parks, and provides water for 40 million people across the arid west. It is also the most endangered river in America. This article outlines a case study of the Upper Colorado River Endangered Fish Recovery Program (UCREFRP), a collaborative effort designed to restore the Colorado pikeminnow population on a section of the Colorado River known as the imperiled 15-mile reach. After years of failed litigation, stakeholder efforts to develop water management solutions led to the establishment of the collaborative. This case study elucidates how collaborative governance efforts take shape, and how they can be more comprehensively assessed by drawing on interdisciplinary approaches from natural and social sciences. This case is an enduring example of the way trade-offs and power imbalances must be managed in collaborative governance, and introduces the importance of environmental and ecological justice, that is, how the collaborative process and benefits of collaborative solutions can be distributed more equitably across social and nonhuman stakeholders.”