There are more than 2,400 zoos to visit in the U.S., each one packed with animals from near and far. Most major cities have a zoo or aquarium, making these fascinating venues a great day trip on any vacation. Zoos in the United States have the added benefit of contributing to research and conservation efforts. Many are working toward providing open-air, cageless enclosures for their animals, resulting in happier creatures in a natural environment. For frequent zoo-goers, memberships help support the care and maintenance of animals and their habitats.

01The San Diego Zoo

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The San Diego Zoo is the largest zoo in the United States, housing over 3,700 animals encompassing more than 650 species. This zoo is unique in that it led the charge of open-air, cageless enclosures for animals and is one of the only zoos in the world to successfully breed the giant panda. The newest exhibit, added in 2017, is called Africa Rocks and cost over $60 million to construct.

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02Smithsonian Conservation Biology Institute

Close up of a Grand Cayman (a.k.a. Blue, Cyclura lewisi) iguana resting on a rock at the Smithsonian National Zoo.

The Smithsonian's National Zoo & Conservation Biology in Washington D.C. has led the way in mitigating animal extinction for over 100 years. Learn about the zoo's past in discovering diseases that threaten elephants in the Elephant Community Center or check out how scientists at the zoo work to safely and healthily breed cheetahs. Children will get a kick out of the Kid's Farm exhibit, home to a variety of farm animals just waiting to be fed tasty treats!

03The Indianapolis Zoo

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The Indianapolis Zoo wins the award for most creative activities! Not only can you view over 1,400 animals and 31,000 plants, but you can swim with dolphins, attend zoo camp, and obtain a personalized animal portrait from a zoos artist. Make sure you don't miss the new long-tailed macaques who love swimming in the water in the hot summer months.

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04The Bronx Zoo

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It's hard to imagine a flourishing zoo filled with lush plants and vivacious animals in the middle of a metropolis like New York City, but the Bronx Zoo offers one of the neatest zoo experiences in the country. The Bronx Zoo is notable for its amazing attention to detail in creating natural habitats that make the animals happy year-round. Add a little adventure to your trip to the zoo: sail on a zipline at the new aerial adventure park.

5. Oakland Zoo

The Oakland Zoo is known and loved around the world for its unparalleled native and exotic animal care, as managed by the Conservation Society of California. Here, you can traverse trails filled with wildlife from different parts of the world, including Africa, Australia, and The United States. You can also get your very own glimpse at conservation efforts in the zoo's 17,000 square foot veterinary museum.

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05The Alaska Zoo

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Alaska has some of the most unique wildlife in the U.S., so it is no surprise that it has an impressive zoo to match. Because of the cold climate, the Alaska Zoo can house animals the southern states can't accommodate. At the Alaska Zoo, you will find snow leopards, Canadian lynx, and reindeer. One of the most beloved elements of this zoo is its efforts to rescue and care for injured and abandoned polar bear cubs.

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06Fort Worth Zoo

Roseate Spoonbills are found mostly in Florida and coastal Texas. tmarvin / Getty Images

The Fort Worth Zoo in Texas is not only home to 7,000 exotic animals but also to many animal-focused events and activities. Highlights include Homework Help, Animal Outreach, and Parents Night Out, where kids have the evening to explore the park while parents get a night to themselves. You can also book yourself a VIP experience at the zoo with the opportunity to have a personal look at some of the zoo's most popular animals.

07Woodland Park Zoo

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Woodland Park Zoo in Seattle, Washington, is a zoological garden that works hard to recreate the natural habitats of its more than 1,000 animals. The Association of Zoos and Aquariums has honored Woodland Park Zoo with multiple awards for Best National Exhibit. Visitors enjoy watching Aibeck grow up. This snow leopard cub was born at the zoo in the summer of 2017.

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08St. Louis Zoo

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The Saint Louis Zoological Park is recognized as a leading zoo in animal management, research, conservation, and education. Thanks to a public subsidy from a cultural tax district, entrance to the zoo is completely free. The biggest attraction at the St. Louis zoo is Kali, an 850-pound polar bear who lives in a brand new $16 million enclosure. The Africa exhibit is also a can't-miss spot.

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09The Houston Zoo

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The Houston Zoo is the second most visited zoo in the United States, with over 2.5 million visitors every year. Even if you can't make it to Texas, you can check in with the animals via the zoo's Rhino, Elephant Yard, and Leafcutter Ant online cams. The zoo is home to one of the largest collections of birds in the United States and you can even spend the night at a zoo sleepover.

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10Busch Gardens Tampa

Closeup of a hippopotamus underwater as it swims at Busch Gardens Tampa Photo by Anthony Kind on Unsplash

Florida is already home to an abundance of wildlife, but none can match those found at the zoo in Busch Gardens Tampa. Given the Humane Certified animal welfare seal from American Humane, Busch Gardens Tampa provides protected areas for endangered species like Asian elephants. The Serengeti Plain is a can't-miss experience for any visitor here, where you can see animals up-close on an open-air touring vehicle.

11The Columbus Zoo

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Famous animal researcher and late-night TV guest Jack Hanna is the director emeritus of the Columbus Zoo. Hanna's efforts and promotion have made this one of the top zoos in the United States. A unique aspect of the zoo is its 100,000-gallon coral reef tank teeming with bright tropical fish. Also, be sure to check out the Congo exhibit.

12The Cincinnati Zoo

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The Cincinnati Zoo and Botanical Garden is the second oldest zoo in the United States, with a Reptile House dating back to 1875. Although the zoo has been in headlines in recent years for the unfortunate death of its gorilla Harambe, it works hard to save species by breeding animals in a safe and healthy environment. One of guests' favorite activities is getting to know Moe, the adorable two-toed sloth.

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13Henry Doorly Zoo

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The Henry Doorly Zoo and Aquarium is located in Omaha, Nebraska, and is known for its glazed geodesic dome. Inside the dome, find an homage to the American Southwest, including dunes, desert, reptiles, and bobcats. Go one level lower to the dark, nocturnal exhibit where you can see naked mole rats and bats.

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14Audubon Zoo New Orleans

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There are 58 acres of fun to be had at Audubon Zoo New Orleans, part of the Audubon Nature Institute. The wildlife at Audubon Zoo New Orleans is diverse, with animals ranging from white alligators to thorny devil stick insects. You can catch a number of daily animal presentations here, as well as plenty of animal feeds to the big cats like tigers and leopards.