The U.S. Army Corps of Engineers undertakes activities to maintain navigable channels, reduce flood and storm damage, and restore aquatic ecosystems. Congress directs the Corps through authorizations, appropriations, and oversight of its studies, construction projects, and other activities. The Corps must be authorized to undertake an activity; the authorization can be project-specific, programmatic, or general. While generally necessary, authorizations usually are insufficient for a Corps study or construction project to proceed; the agency’s ability to act on an authorization requires funding. This report summarizes congressional authorization and appropriations processes for the Corps. It also discusses agency activities under general authorities.