This dissertation examines the ideas, practices, and effects of state-led development programs in indigenous communities of Mexico during the mid-twentieth century. Using Mexico’s first experiment with integrated regional development as a case study, it centers on the relocation of over twenty thousand inhabitants of the Papaloapan River Basin, most of them indigenous, who were displaced by the construction of Latin America’s largest hydroelectric dam. Leading the exodus of the indigenous population was a cadre of Mexican anthropologists, who drew from their reported expertise in indigenous culture and society to facilitate among the relocated indigenes a culturally-sensitive transition to modern life. By focusing on the interactions between the displaced population, anthropologists, agricultural engineers, local politicians and agrarian activists in the Papaloapan, the dissertation argues that development—as a process and not simply an a priori policy prescription—shaped social scientific ideas and practices, the consolidation of state power, and the very concept of “indigenous” as not merely an ethnic denotation but a salient political category to demand access to state resources in modern Mexico. This is the first historical study of modern Mexico to connect the plans and practices of economic development to indigenous politics. It upends longstanding assumptions about the power and coherence of the Mexican state during the mid-twentieth century by examining how planners worked with the local people and landscape as they carried out a project for infrastructural, economic, and social improvement. Through an analysis of projects and politics as they played out on the ground during relocation and upon resettlement, the thesis challenges prevailing scholarship that presumes parity among actors executing the so-called will of the government, to reveal the limitations of state knowledge and power in 1950s Mexico, and the malleability of the very social and political categories—among them the category “indigenous”—that justified calls for improvement. The dissertation represents a departure from not only literature on modern Mexican history, but also the history of Cold-War era development throughout the world.