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Updated 03/04/2021: The Endangered Species Act of 1973 (ESA; P.L. 93-205, 87 Stat. 884, 16 U.S.C. §§1531-1544) aims to conserve species listed as endangered or threatened under the act. Under the ESA, it is the policy of Congress that all federal agencies shall seek to conserve threatened and endangered species, use their authorities in furtherance of the ESA, and cooperate with state and local agencies to resolve water resource issues in concert with conserving endangered species. The ESA is administered by the U.S. Fish and Wildlife Service (FWS) and the National M arine Fisheries Service (NMFS). Under the ESA, domestic and foreign species of animals (both vertebrate and invertebrate) and plants can be listed as either endangered or threatened, according to an assessment of the risk of their extinction. Once a species is listed, the act provides tools to aid the species’ conservation and recovery and to protect its habitat. The ESA and its predecessors have been in place since 1966. Since enactment, these acts have led to the listing of over 2,400 species as threatened or endangered. As of October 2020, 2,363 species were listed, the majority of which (71%) were listed in the United States; the remaining 29% were foreign species. Of all listed species in October 2020, 79% were endangered and 21% were threatened. As of October 2020, 91 species had been delisted under the ESA since it was enacted in 1973, which is approximately 3.7% of the total number of species ever listed under the act. Many Members of Congress are interested in how the ESA is implemented, because states—as well as American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, the Virgin Islands, outlying Islands in the Pacific and the Caribbean, and Washington, DC—have species that are, or may be in the future, listed under the act. Congress also is interested in broader issues surrounding the ESA and oversight of its implementation, primarily because some stakeholders perce