Despite five decades of experience, there is a considerable gap in legal and empirical study on the impacts of the National Environmental Policy Act (NEPA). Proponents of reform often claim NEPA litigation is a major obstacle for federal actions; others have concluded litigation is not a major contributor of project cost escalation or delays. This Article studies the incidence and conditions of infrastructure project litigation under NEPA, using a data set of 355 major transportation and energy infrastructure projects that completed a federal environmental study between 2010 and 2018.