Since America’s first zoo, the Philadelphia Zoo, opened in 1874, zoos have played an important role in wildlife conservation and public education about wildlife in the United States. Over time, they’ve evolved from small exhibition spaces to vast parks that offer everything from breeding programs to immersive activities and overnight stays. Today, 226 institutions across the country are members of the Association of Zoos and Aquariums (AZA). Check out 13 of the largest zoological parks in the U.S., all of which are AZA-accredited and ranked below by the number of animals they house.
13. Dallas Zoo – Dallas, Texas
Number of animals: over 2,000
Created with just two deer and two mountain lions in 1888, Dallas Zoo is the oldest zoo in Texas. The 2,000-plus animals at the zoo represent over 400 species and live in habitats spread across 106 acres. One of the most notable areas is the Giants of the Savannah exhibit, where elephants, giraffes, and lions roam freely around a vast habitat. Visitors can also observe giraffe and tortoise feedings, in addition to bird of prey displays. Meanwhile, school-age children can enroll in single-day and weeklong summer camps that offer fascinating behind-the-scenes educational experiences.
12. Zoo Miami – Miami, Florida
Number of animals: over 2,000
Zoo Miami (also known as the Miami-Dade Zoological Park and Gardens) is Florida’s largest and oldest zoo. Established in 1948, it occupies 750 acres and has 4 miles of walkways offering views of over 2,000 animals. The animals here represent more than 375 species from Asia, Africa, Australia, and the Americas. Of these, around 130 are considered endangered.
Animals at Zoo Miami are grouped according to their native region. You’ll find African elephants and lions, Sumatran tigers, and western lowland gorillas from the Congo Basin, among many other notable species. Visitors can also explore a butterfly garden and succulent garden, join a nocturnal tour, or rent a Safari Cycle to explore the zoo.
11. National Zoo – Washington, D.C.
Number of animals: over 2,200
Opened in 1889, the National Zoo in D.C. is part of the world-famous Smithsonian Institution. Admission is free to see the zoo’s more than 2,200 animals that represent 400 species. Popular attractions include the Reptile Discovery Center, featuring Komodo dragons, and the Asia Trail, which is home to a habitat of giant pandas.
Daily talks and demonstrations highlight the life and conservation of Andean bears, big cats, and primates, among other animal residents. Special events at the zoo include an adults-only Halloween party and holiday season light displays. On hot days, visitors are also invited to cool off in the Squirt Zone wading pool.
10. Riverbanks Zoo and Garden – Columbia, South Carolina
Number of animals: over 3,000
Riverbanks Zoo and Garden is home to over 3,000 animals, from the American flamingo and red kangaroo to the Galapagos tortoise and leopard shark. About 400 species live within the South Carolina zoo’s 170 acres. Hands-on activities here include giraffe, tortoise, and lorikeet feeding programs, along with behind-the-scenes viewings of the zoo’s western lowland gorillas.
Complementing the animals is the lush and technicolored Riverbanks Botanical Garden. It spreads across 70 acres and has 10 themed areas displaying more than 5,700 native and exotic plants. Gardening enthusiasts can sign up for horticulture classes and workshops.
9. Brookfield Zoo Chicago – Brookfield, Illinois
Number of animals: over 3,400
Spreading across 216 acres in the western Chicago suburb of Brookfield, this zoo is home to over 3,400 animals and more than 511 species. Since opening in 1934, the Brookfield Zoo has been a pioneer in animal conservation. It was one of the first zoos in the country to introduce barless exhibits. The first panda exhibited in the United States arrived at Brookfield Zoo in 1937, and in 1941, Georgie-Joe was the first black rhino born in a zoo.
The Animal Loops are the best way to discover the zoo today. The five color-coded trails include the Bird and Reptile Loop, the Large Animal Loop, the Carnivore and Pinniped, the Small Child Loop, and the Nature Walk. Visitors can also see the many habitats via the Motor Safari or partake in behind-the-scenes encounters with flamingos, giraffes, penguins, and sharks.
8. Minnesota Zoo – Apple Valley, Minnesota
Number of animals: over 4,500
When it opened in 1978, Minnesota Zoo was recognized for its innovative approach to animal exhibits. It was one of the first zoos in the U.S. to organize displays by habitat rather than species. It’s also one of the few state-supported zoos in the country.
Today, the Minnesota Zoo shelters over 4,500 animals and has an annual visitation of around 1.3 million guests. Here, visitors can discover African fruit bats, Malayan tapir, and other curious creatures among the 500-plus species. A highlight is Discovery Bay, a marine education center home to Hawaiian monk seals, seadragons, seahorses, and a 218,000-gallon shark tank.
7. Houston Zoo – Houston, Texas
Number of animals: over 6,000
Houston Zoo is a 55-acre wildlife center situated in Hermann Park, in the Houston Museum District. It shelters over 6,000 permanent residents that represent over 600 species. It also contributes to 49 conservation programs in 27 countries.
Notable exhibits include the African Forest — home to chimpanzees, gorillas, rhinos, and ostriches — and Birds of the World, a popular area consisting of three aviaries focusing on African, North American, and South American birds. Visitors can also purchase guided encounters with anteaters, elephants, Galapagos tortoises, and penguins. There are overnight programs for all ages, and adults can register to be part of the 350-strong volunteer team.
6. Kansas City Zoo and Aquarium – Kansas City, Missouri
Number of animals: over 10,000
Kansas City Zoo and Aquarium occupies 202 acres in the northern section of Swope Park. Its 10,000-plus inhabitants represent 200 species and are split between a zoological park and the Sobela Ocean Aquarium. The zoo opened in 1909 with an animal collection that included four lions, three monkeys, a wolf, a fox, a coyote, a badger, and a lynx, along with an eagle and other birds. Today, everything from African elephants and polar bears to porcupines have been added to the zoo’s roster.
Sobela Ocean Aquarium opened in 2023 as an educational center to showcase how ocean currents connect the world. It features a 650,000-gallon exhibit space divided into six sections and 34 habitats. The aquarium alone is home to approximately 200 species, including clownfish, sharks, and stingrays.
5. Columbus Zoo and Aquarium – Powell, Ohio
Number of animals: over 10,000
Founded in 1927, Columbus Zoo and Aquarium welcomes an estimated 2.2 million annual visitors, who come to discover over 10,000 animals from around 600 individual species. In 1956, the zoo achieved international fame with the birth of Colo, the first gorilla born under human care.
Famed American zookeeper Jack Hanna, the zoo’s director from 1978 to 1992, was responsible for incorporating exhibits such as the African Forest and Manatee Coast. The latter is a rescue and rehabilitation clinic for the Florida manatee. Other popular areas include Discovery Cove, home to seals and sea lions, and Polar Frontier, where brown bears and polar bears roam.
4. Bronx Zoo – New York City, New York
Number of animals: over 11,000
Bronx Zoo covers 265 acres and features more than 11,000 animals representing around 650 species. It’s the headquarters and flagship park of the Wildlife Conservation Society, an organization dedicated to advanced wildlife conservation and zoology education. From the American alligator and African wild dog to the Cuban parrot and Magellanic penguin, the zoo’s residents come from all corners of Earth.
One of the Bronx Zoo’s most popular attractions is the Congo Gorilla Forest, a 6.5-acre exhibit where gorillas live alongside hornbills, mandrills, okapi, and approximately 400 plant species. Another is the Dinosaur Safari, a Jurassic journey with 60 life-size animatronic dinosaurs and fossil digging activities.
3. St. Louis Zoo – St. Louis, Missouri
Number of animals: over 12,000
The St. Louis Zoo opened in 1910 with the formation of the Zoological Society of St. Louis. Covering 90 acres in the city’s Forest Park, it’s now home to over 12,000 animals and 450 different species. Animals are split into six individual zones, each accessible via paved walkways and the Emerson Zooline Railroad. At the Discovery Center, you can see more than 100 species of live insects. The Wild is home to apes, bears, and penguins, and you can spot sea lions, seals, and stingrays at Lakeside Crossing.
Visitors can sign up for hands-on programs ranging from vet hospital tours to bear training sessions and seasonal tours with zookeepers. Also look out for specialty events such as animal-inspired theater shows.
2. San Diego Zoo – San Diego, California
Number of animals: over 12,000
Home to over 12,000 rare and endangered animals representing 680 species, San Diego Zoo is one of the most famous zoos in the world. This 1,000-acre park is located within the city’s historic Balboa Park. It’s managed by the nonprofit San Diego Zoo Wildlife Alliance, which also manages the larger San Diego Zoo Safari Park.
The zoo is notable for its cageless exhibits and authentic replicas of natural habitats. A few of the most beloved areas include Polar Bear Plunge, featuring more than 30 Arctic animals, and Panda Ridge, currently home to two giant pandas. An easy way to explore the exhibits is via the 35-minute guided bus tour and Skyfari Aerial Tram, which offers bird’s-eye views. The park is also a designated botanical garden, showcasing some 700,000 plants.
1. Henry Doorly Zoo and Aquarium – Omaha, Nebraska
Number of animals: over 17,000
The Henry Doorly Zoo and Aquarium has come a long way since it opened as Riverview Park in 1894. From an early collection of around 120 animals, the zoo has grown to become the largest zoo in the United States by animal numbers. Today, it houses more than 17,000 animals (from 962 species) in 20 unique exhibits spread around 160 acres of parkland. Species such as the red panda, orangutan, Indian rhino, and lemur all roam here.
A particular highlight is the Desert Dome, the world’s largest indoor desert, housed under the largest glazed geodesic dome in the world, according to the zoo’s website. It features recreations of the Namib Desert, the Red Center of Australia, and the Sonoran Desert of the southwestern U.S. and Mexico. Also popular is the Lied Jungle, which highlights the biodiversity of rainforests in Africa, Asia, and South America.
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