1. Bronx Zoo - Located in New York City, New York, the Bronx Zoo is the largest metropolitan zoo in the United States and covers an area of 265 acres.
2. Henry Doorly Zoo and Aquarium - Situated in Omaha, Nebraska, the Henry Doorly Zoo and Aquarium is renowned for its diverse collection of animals and exhibits, including the largest indoor desert and nocturnal exhibits in the world.
3. San Diego Zoo - Located in San Diego, California, the San Diego Zoo is known for its extensive collection of rare and endangered species and its commitment to conservation efforts.
4. Columbus Zoo and Aquarium - Situated in Powell, Ohio, the Columbus Zoo and Aquarium is known for its large and diverse animal collection and its emphasis on conservation education.
5. Dallas Zoo - Located in Dallas, Texas, the Dallas Zoo is home to a wide range of animal species and is recognized for its successful breeding programs, particularly for endangered species.
6. Smithsonian's National Zoo - Situated in Washington, D.C., the National Zoo is operated by the Smithsonian Institution and is known for its giant panda breeding program.
7. Philadelphia Zoo - Located in Philadelphia, Pennsylvania, the Philadelphia Zoo is one of the oldest zoos in the United States and houses a diverse collection of animals in a beautifully landscaped setting.