The U.S. Forest Service issued a request for proposals to develop, for recreational purposes, approximately 80 acres of undeveloped, naturally-beautiful land in the Sierra Nevada Mountains of California called the Mineral King Valley. The winning bidder, Walt Disney Enterprises, Inc., proposed a $35 million complex of motels, restaurants, swimming pools, parking lots, a highway, a ski resort, and other structures to accommodate 14,000 visitors daily. Representatives of the Sierra Club (plaintiff), a membership entity with a special interest in national parks and land conservation, filed suit in federal district court against Morton, the Secretary of the Interior, and others (defendants) seeking declaratory and injunctive relief pursuant to the Administrative Procedure Act (APA), 5 U.S.C. § 701 et seq., to prevent the Mineral King Valley development. After a hearing, the district court granted Sierra Club’s request for injunction. Defendants appealed. The court of appeals reversed, and held that the Sierra Club lacked standing to present a justiciable claim. Additionally, the appellate court held that the Sierra Club had not made an adequate showing of irreparable injury and likelihood of success on the merits to justify issuance of the injunction. The U.S. Supreme Court granted certiorari to review.