San Diego Zoo (San Diego, California) - Known for its extensive collection of animals and botanical gardens.
Bronx Zoo (New York City, New York) - One of the oldest and largest metropolitan zoos in the United States.
Columbus Zoo and Aquarium (Columbus, Ohio) - A large zoo known for its conservation efforts and wide variety of species.
Houston Zoo (Houston, Texas) - Situated within Hermann Park, it houses over 6,000 animals.
Philadelphia Zoo (Philadelphia, Pennsylvania) - One of the first zoos in the United States, known for its conservation programs.
Oregon Zoo (Portland, Oregon) - Located within Washington Park, it focuses on conservation and animal welfare.
Denver Zoo (Denver, Colorado) - Home to over 4,000 animals representing 650 species.
Smithsonian's National Zoo (Washington, D.C.) - Part of the Smithsonian Institution, it features over 2,700 animals.
Saint Louis Zoo (St. Louis, Missouri) - Known for its diverse collection and conservation efforts.