This dissertation is an ethnographic study of environmental politics in the Nicaragua/Costa Rica borderlands, wetlands, and waters. It explores the history of state bordering projects and other processes that have made the border, such as the Sandinista Revolution, the Contra War, postwar peace projects, and agricultural development. It also examines the role of borderland residents, protected areas, and transborder waterways in the making and unmaking of the Nicaragua/Costa Rica border. I build on the anthropology of conservation by showing how protected areas can be spaces of abandonment and neglect. I look at how borderland residents mobilize these abandoned wildlife refuges in their political and environmental protests. It is a waterscape ethnography; the chapters trace stories along different bodies of water, showing how water connects people, places, and histories across this border.