Environment Planet Earth 11 Nationally Protected Wetlands You Should Know About By Catie Leary Writer and Photographer Georgia State University Catie Leary writes and curates visual stories about science, animals, the arts, travel, and the natural world. our editorial process Catie Leary Updated May 30, 2021 The wetlands of Congaree National Park offer a glimpse of what South Carolina looked like in centuries past. Mark C Stevens / Getty Images Share Twitter Pinterest Email Planet Earth Conservation Weather Outdoors Wetlands are one of the world's most biologically diverse and fragile ecosystems. Described as areas that are saturated for much or all of the year, wetlands include marshes, swamps, wet grasslands, mangroves, and other coastal areas. Wetlands are highly efficient systems that maintain water quality and control floods and erosion. In the U.S., more than one-third of all threatened and endangered species live exclusively in wetlands. Throughout America and the world, wetlands have suffered at the hands of humans. According to the National Park Service, "less than half of the wetland acreage that existed in the lower 48 states at the time of European settlement remains today." In response to this ecological degradation, hundreds of millions of acres of wetlands across the country are now being managed through various wilderness designations, including national parks, national wildlife refuges, and national seashores. Here are 11 nationally protected wetlands you should know about. 1 of 11 Everglades National Park (Florida) Marie Hickman / Getty Images One of the most iconic wetlands in the United States is Everglades National Park in southern Florida. Named a UNESCO World Heritage Site, Everglades National Park has the Western Hemisphere’s largest stand of mangroves, an important and biologically diverse ecosystem. This vast subtropical wilderness of cypress swamps, mangrove forests, pineland, and hardwood hammocks is home to many endangered species, including West Indian manatees, American crocodiles, and Florida panthers. Although it is the third-largest national park in the contiguous U.S., only 20% of the original 100-mile-long Everglades watershed is included within the 1.5 million acres that currently make up the national park. Some portions remain intact under other federal and state wilderness designations, but about 50% of the original Everglades wetlands have been irrevocably destroyed by rapid agricultural and urban development that began in the 19th century. 2 of 11 Merced National Wildlife Refuge (California) Spondylolithesis / Getty Images From Yosemite to Big Sur, the state of California is positively brimming with outstanding scenic vistas. One haven for scenic nature is Merced National Wildlife Refuge, a 10,258-acre refuge that provides wetlands and vernal pools to support migrating birds. Located two hours south of Sacramento, this birder's paradise hosts winter populations of sandhill cranes and Ross’s geese, as well as waterbirds, shorebirds, and waterfowl. 3 of 11 Okefenokee National Wildlife Refuge (Florida and Georgia) lauradyoung / Getty Images Straddling the border of Georgia and Florida is the Okefenokee, the largest blackwater swamp in America and one of the world's largest remaining intact freshwater ecosystems. Much of the swamp is populated with bald cypress, swamp tupelo, and other wetland flora. The drier upland areas are filled with massive evergreen oaks and towering forests of longleaf pine. While these upland areas are home to wild turkeys, bobcats, white-tailed deer, and Florida black bears, the rich swampland fosters important wetland habitats and breeding grounds for wading birds, alligators, turtles, lizards, and many species of amphibians. 4 of 11 Great Dismal Swamp National Wildlife Refuge (North Carolina and Virginia) Sean Russell / Getty Images Contrary to its name, the Great Dismal Swamp, a wildlife refuge that straddles North Carolina and Virginia, offers outstanding opportunities for birdwatching, hiking, canoeing, fishing, and boating. Although FWS currently manages about 112,000 acres of the Great Dismal, it's estimated that the original size of the vast swampland prior to human encroachment was around 1 million acres. 5 of 11 Death Valley National Park (California and Nevada) Stan Shebs / Wikimedia Commons / CC BY-SA 3.0 You might not think the hottest and driest place in North America could include a natural wetland, but it does. Saratoga Springs is a desert oasis situated along the southern tip of Death Valley National Park. This marshy, spring-fed wetland is an important home to multiple endemic marine species, including the Saratoga Springs pupfish. A massive 3,422,024 acres, Death Valley National Park is the largest national park in the lower 48 states. 6 of 11 Cumberland Island National Seashore (Georgia) Dan Reynolds Photography / Getty Images The crown jewel of Cumberland Island is its 17-mile-long stretch of undeveloped beach, but this remarkable slice of Southern paradise is also home to an extensive 16,850-acre wetland system that includes salt marshes, tidal creeks, and mudflats. In addition to typical wetland wildlife, it's not uncommon to spot Cumberland's iconic feral horses grazing and wading through the island's marshland and mudflats. Although it's quite magical to observe these charismatic equines from afar, the animals' invasive grazing and trampling of these fragile ecosystems have become a serious point of contention among conservationists and the larger public. 7 of 11 Kenai National Wildlife Refuge (Alaska) Wildnerdpix / Getty Images The eastern coast of the U.S. tends to get all the glory for its vast yet fragmented concentration of marshes and swamps. However, Alaska contains 63% of all wetlands in the United States (excluding Hawaii). Wetlands cover about 43% of the state of Alaska (over 174 million acres). The vast majority of Alaska's wetlands, like those in Kenai National Wildlife Refuge, exist in peace under state and national protections. The grass wetlands are home to a variety of birds including the short-eared owl and the northern harrier; the sedge wetlands host red-necked and horned grebes, among others. These areas are particularly vital in the summer, when they are used by migratory birds as staging and breeding grounds. 8 of 11 Biscayne National Park (Florida) stockphoto52 / Getty Images Located off the southern coast of Miami, 95% of this 172,971-acre national park is covered by water. The park protects the coastal wetlands and open waters of Biscayne Bay as well as its adjacent coral limestone barrier islands, including Elliott Key (the first of the Florida Keys). Perhaps the most astounding wetland environment found in Biscayne National Park is its extensive shoreline mangrove forest. Mangroves are characterized by their complex root system, which is capable of surviving immersion in saltwater as well as anoxic (low-oxygen), waterlogged mud. Mangrove swamps are unique ecosystems that provide shelter to several threatened wildlife species, from the mangrove cuckoo to the American crocodile. 9 of 11 Klamath Marsh National Wildlife Refuge (Oregon) estivillml / Getty Images This 40,000-acre refuge in southern Oregon was established in 1958 to protect the vital nesting, feeding, and staging habitats of migratory birds, including sandhill cranes, yellow rails, and various species of waterfowl. The wetland consists of wet grassy meadows and stretches of open water. The marsh is also home to the Oregon spotted frog, a vulnerable species that relies on the shallow, aquatic habitat for breeding. 10 of 11 Congaree National Park (South Carolina) Mark C Stevens / Getty Images Just a few centuries ago, the vast majority of South Carolina was covered in old-growth, bottomland hardwood forest. Sadly, after rampant agricultural and logging development wreaked havoc on the land, only a tiny fraction of this special floodplain forest remains in the nearly 27,000-acre Congaree National Park. In 1983, UNESCO designated the unique Congaree ecosystem—including Congaree National Park—a Biosphere Reserve. 11 of 11 Merritt Island National Wildlife Refuge (Florida) VisionsbyAtlee / Getty Images The 140,000-acre Merritt Island National Wildlife Refuge is filled with salt marshes, estuaries, sand dunes, and hardwood hammocks. NASA originally acquired the land in 1962, and the Kennedy Space Center is located within the refuge. This diverse landscape is home to a plethora of wildlife, including sea turtles, alligators, bobcats, Florida panthers, and numerous birds. On any given day, you may see roseate spoonbills, ibises, ospreys, anhinga, herons, egrets, and various species of waterfowl, rails, and shorebirds. In addition to its status as a top-notch birding destination, the refuge also offers opportunities to observe West Indian manatees in the wild.