Th e Columbia Basin Project (CBP) is the largest comprehensive reclamation project in the United States. An intertwined system of water diversion, capture, storage, movement, and use for hydroelectric production and irrigation, made famous by the capstone of Grand Coulee Dam, the CBP completely transformed the arid environment of central Washington and the economy of the Pacifi c Northwest (PNW). As this project stretches now into 75 years of plans, actions, reactions, and potential future actions, there is a surprisingly small amount of literature examining this project and its far-reaching implications. Originally planned as a reclamation project, the CBP morphed over time as values and priorities changed; never achieving completion, approximately two-thirds of the original planned project acreage is currently irrigated, but with escalating ecologic and economic implications. Th e most obvious ecologic implication has fi xated debates about development in the Pacifi c Northwest, and that is the near annihilation of historic salmon runs due to dam construction. As this question (salmon versus dams) consumes most scholarly literature related to the CBP, we chose instead to examine everything except ecologic implications. Th is article reviews the existing literature on the CBP from several fi elds, noting that many economic, social, legal, policy, and agricultural questions remain unanswered aft er 75 years. Th ose unanswered questions become particularly important in light of recent discussions within Washington State concerning completing the CBP, thus potentially increasing the size of irrigated lands by one-third in the Columbia Basin Project.