Abstract: By any metric, the St. Lawrence Seaway is a marvel of 20th century engineering. Completed in 1959, it unified several discrete elements into a coherent technological system, facilitating navigation and the production of hydroelectricity. Moreover, it is perceived as a manifestation of the amicable relationship between Canada and the United States, becoming a trope for transnational cooperation. The Seaway has become a technological black-box, which this study opens. In addition to the project’s merits, I explore the people, values, and practices marginalized or transformed by the Seaway project and discourse. The Seaway inexorably transformed the river and adjacent landscape, and, I contend, exercised further transformative power. This study shows that the reordering of the St. Lawrence concomitantly and reciprocally reordered people’s relationships to the river, and with one another. By teasing out the values concealed by the dominant Seaway discourse, this project will show that as we reconstruct rivers, we reconstruct ourselves.