My dissertation examines the history of the trans-desert pipeline system that exported Iraq's oil to European markets via the Mediterranean. Referred to as Iraq's "third river", the pipeline was built in 1935 by an international oil consortium, the Iraq Petroleum Company (IPC), and ran from the oil fields of northern Iraq to two points on the coasts of Lebanon and Palestine, crossing the borders of five states. Existing studies of Iraq's oil development rarely consider the fact that oil infrastructure extended beyond the territorial boundaries of the nation-state, focusing instead on the effects of oil revenues on Iraqi political and social structures. Placing the pipeline at the center of my study provides an alternate analytical lens through which to understand the history of oil in the Middle East, one that does not take as its starting point the established frameworks of national or corporate histories. By tracing the history of the pipeline's construction during a period of colonial rule and its subsequent operation in the second half of the twentieth century, I examine the ways in which the material flows of Iraq's oil inscribed borders, transformed physical and social environments, and produced new political configurations. Rather than viewing the pipeline as a passive conduit for the delivery of oil and its transformation into revenues, I suggest that the pipeline's structure and its fixity in space both reflected and shaped a set of shifting relationships between imperialism, nationalism, and the international oil industry.