© 2019, © 2019 American Association of Geographers. Although often viewed as serving as a public good, infrastructure can have important political effects resulting from the way in which it is designed, built, and managed that preexist its stated or implied technical goals. It acts as a mediator and enforcer of state interests, defining the ways in which the state can enter everyday life and, in turn, it shapes the possibilities of life around the goals of the state. Although this politics of infrastructure has seen renewed interest from geographers, anthropologists, and other social scientists concerned with the power of artifacts, the role that infrastructure plays in defining and characterizing the particularly nationalist and racialized state remains undertheorized. Through a genealogy of water control infrastructure in Guyana, I show how apparently banal aspects of everyday life, such as infrastructure, can play an important role in the rise of an authoritarian government, first colonial and later postcolonial. Because 90 percent of Guyana’s population and most of the nonmineral economic resources are below sea level, water control infrastructure plays an important functional role in the country. Rather than just a means for preventing coastal flooding and irrigating the patchwork of sugar and rice fields that define the economy, however, I argue that this infrastructure played a key role in driving ethnic divisions between laborers in the colonial era that undermined anticolonial sentiment and laid the groundwork for the creation and perpetuation of an ethnic nationalist and authoritarian postcolonial regime. Key Words: colonialism, flooding, infrastructure, race, water.