Federal environmental assessments are reviews required under the federal Impact Assessment Act for designated projects that may cause significant environmental effects in areas of federal jurisdiction. Projects triggering federal assessment include major mines, pipelines, nuclear facilities, large transportation projects, and undertakings affecting federal lands, fish habitat, or migratory birds. Municipal infrastructure projects occasionally require federal review—a major wastewater outfall affecting fish habitat, for example. Federal assessments add time and cost to project development, as proponents must conduct studies, engage Indigenous communities, hold public consultations, and address agency concerns. While some view assessments as unnecessary delays, others see them as essential environmental protection. Assessment requirements have been politically contentious, with recent legislation attempting to balance thorough review with timely decisions. Understanding when federal assessments apply helps municipalities plan project timelines realistically.