The Environmental Protection Agency (EPA) and the Department of the Army ("the agencies") are amending the Code of Federal Regulations (CFR) to conform the definition of "waters of the United States" to a 2023 Supreme Court decision. This conforming rule amends the provisions of the agencies' definition of "waters of the United States" that are invalid under the Supreme Court's interpretation of the Clean Water Act in the 2023 decision. This final rule is effective on 8 September 2023. POC is Whitney Beck, Oceans, Wetlands and Communities Division, Office of Water (4504T), EPA, 1200 Pennsylvania Avenue NW, Washington, DC 20460; tele: (202) 564–2281; email: CWAwotus@epa.gov. citation(Federal Register 8 September 2023 [Rule] Pages 61964-61969)