The Fish and Wildlife Service designated a Louisiana tract used as a commercial timber plantation as critical habitat for the endangered dusky gopher frog, even though the frog had not lived there for decades and the site would require modification to support a population. The landowners challenged both the designation and the Service’s decision not to exclude the tract after estimating that designation could eliminate millions of dollars in development value. The Supreme Court vacated and remanded. The Endangered Species Act authorizes designation only of habitat for the species, so the Court of Appeals had to decide in the first instance whether the tract qualified as habitat and whether the administrative record supported the Service’s findings. The Court also held that the Service’s decision not to exclude the tract was subject to judicial review. Although the agency had discretion to weigh conservation benefits against economic effects, the statute supplied a meaningful standard requiring consideration of those factors. The Court did not decide whether the tract was habitat or whether the Service’s cost-benefit analysis was lawful.