A megaproject half a century in the making, the planning and building of the St. Lawrence Seaway and Power Project is one of the defining episodes in North American history. Possibly the largest construction undertaking in Canadian history, and one of the most ambitious borderlands projects ever embarked upon by two countries, it also required decades of negotiation and the controversial relocation of thousands of people. Negotiating a River looks at the profound impacts of this megaproject, from the complex diplomatic negotiations, political manoeuvring, and environmental diplomacy to the implications on national identities and transnational relations.