We, the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) (collectively referred to as the "Services" or "we"), add a definition of "habitat" to our regulations that implement section 4 of the Endangered Species Act of 1973, as amended (Act). This rulemaking responds to Supreme Court case law regarding the designation of critical habitat and provides transparency, clarity, and consistency for stakeholders.