In the wake of the Gulf oil blowout disaster, there is renewed interest in protecting the freshwater of the Great Lakes from the risks of oil drilling. The region has significant oil resources that would be economically and technologically accessible through drilling in the Great Lakes. The Great Lakes bottomlands and shorelines are subject to the regulatory jurisdiction of two countries—-the United States and Canada—-and eight American states. While the existing legal regime lacks uniformity, and is characterized by jurisdictional inconsistency and potential for transboundary pollution externalities, oil drilling is mostly prohibited. With strong public support for protecting the Great Lakes, there is an opportunity to further strengthen oil drilling regulation in the Great Lakes through international and domestic law.