At the time of its construction (1971-1985), the Tennessee-Tombigbee Waterway was a highly scrutinized public works project, but the years after its construction have remained largely unexplored. Research in the John C. Stennis Collection, U.S. Army Corps of Engineers and Tennessee-Tombigbee Waterway Development Authority archives, and local newspapers, revealed that despite developers’ promise the waterway’s economic impact failed to live up to expectations, while its environmental influence more than exceeded them. Though rural southerners failed to benefit economically from the waterway, they embraced the environmental changes forced upon the project by the National Environmental Policy Act. Built as a promise of economic development, the Tenn-Tom offers a model of how economics and environmental forces intersected within the rural South. The waterway’s history as an economic and environmental force demands a reconsideration of the role of public works projects in southern environmental history.