Many of America’s 63 national parks charge an entrance fee, usually $30-$35 per vehicle or $15 if you’re walking or on a bike. Or you can get an annual pass for just $80. The fee covers you for seven days, and the money goes to a good cause: according to the NPS, 80 percent is used within the park, helping to improve trails, campsites, and roads, and 20 percent goes to other park sites. And there are six or so fee-free days each year.

　　You can also have a national-park experience for free another way, by visiting one of the 20 national parks that don’t charge an entrance fee ever. Come and go as you please without dropping a dime. Many of them are among our least-visited national parks, which means you might have these landscapes to yourself.

　　Looking for more great travel intel? Sign up for Outside’s Destinations newsletter. These are the 20 national parks that are free to visit every day. If youre wondering whether these are good ones, they’re not—they’re great ones.

　　1. Biscayne National Park, Florida

　　A coastal park located in south Florida where the mainland transitions to the Keys, Biscayne National Park is a collection of islands, mangroves, coral reefs, and open water that’s largely inaccessible except by boat. While entering the park doesn’t cost a thing, if you’re bringing a boat and want to anchor at certain areas, expect a $25 docking fee on weekends and holidays.

　　Best Time to Visit: Summer is hot and buggy (with temps in the 90s and mosquitoes), and hurricanes are possible in the fall. Shoot for winter, when temps hover in the mid 70s and the storms and bugs are dormant.

　　Signature Adventure: Biscayne Bay is known for its shipwrecks, and the Mandalay, a schooner that sank in the ’60s, is one of the top sites, as the hull sits in shallow enough water to be seen by snorkelers as well as divers. This wreck is part of the Maritime Heritage Trail, which includes five others. Don’t want to spend your time underwater? Head to Boca Chita Key, also part of the park, a 32-acre island with camping ($25 a night, first-come, first-served), hiking, and a lighthouse. The half-mile trail that circumnavigates the small island leads to its beaches.

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　　2. Channel Islands National Park, California

　　Channel Islands National Park encompasses five rugged islands in the Pacific Ocean about 30 miles off the coast of Los Angeles. If you ever wondered what Southern California would look like without the development and traffic, this is it. The park is full of remote beaches, steep cliffs, expansive meadows, and pristine forests.

　　Best Time to Visit: Summer, as the water and air temps are both in the 70s, a little cooler than most of Southern California but still warm, so you can make the most of those beaches scattered throughout the park.

　　Signature Adventure: I hit Channel Islands last summer as part of a seven-day adventure cruise, but the easiest way (compared to arriving via seaplane or private boat) to reach the park is by ferry, with Island Packers (day trips from $96). Get dropped off on Santa Rosa Island and hike the 12-mile out-and-back to Skunk Point, a prominent peninsula with sand dunes and cliffs jutting into the Pacific. You’ll pass rare Torrey pines, a gnarled-looking, wind-twisted type of tree only found on the Channel Islands and in La Jolla on the mainland, and have copious views of the ocean and island along the way.

　　Or book a sea-kayaking tour with Channel Islands Adventure Company and paddle to sea caves and gaze at natural rock arches (from $145 per person).

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　　3. Congaree National Park, South Carolina

　　You could say Congaree National Park is a swamp, and you wouldn’t be wrong, but the word doesn’t do the place justice. The 26,692-acre Congaree holds the largest intact old-growth bottom-wood forest in the South, boasting trophy-sized loblolly pines and cypress that rise straight from the water. The same forest has one of the tallest canopies in the eastern United States, with an average tree height of more than 100 feet.

　　Best Time to Visit: Avoid summer because of the sweltering heat and bugs. Winter and spring are fine, but you might as well show up in the fall when the weather is perfect, the rivers are full from seasonal rains, and the hardwoods, like tupelos and sweet gums, are popping with color.

　　Signature Adventure: Most of the fun in Congaree is water-based, so bring a canoe or paddle board and slowly make your way through the Cedar Creek Canoe Trail, a 15-mile marked “path” that winds through old-growth cypress. The current is mellow enough to paddle up or downstream, so you don’t need a shuttle.

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　　4. Cuyahoga Valley National Park, Ohio

　　An oasis of public land sandwiched between the bustling cities of Cleveland and Akron, Cuyahoga Valley holds 33,000 acres of forest and historic farmland surrounding the Cuyahoga River. What the park lacks in towering peaks or grand vistas, it makes up for in waterways, waterfalls, and cultural significance; you can ride your bike beside the Ohio and Erie Canal, which connected the Ohio River with Lake Erie, key to the country’s western expansion during the early 1800s.

　　Best Time to Visit: It’s a four-season park (although winters can be cold and snowy), and I could make an argument for every season. Fall brings bright foliage, and spring is mild and uncrowded, but show up in summer and you can take advantage of the many farmers’ markets in and around the park. The Cuyahoga Valley is still a very active agricultural hub of the Midwest.

　　Ohio Erie Canal Towpath

　　Signature Adventure: You have to bike at least a section of the Towpath, a 100-mile crushed-gravel trail that follows the Ohio and Erie Canal. Roughly 20 miles of the Towpath sit inside the park, passing through small towns and meadows full of wildflowers, like trillium and bloodroot, with deer and foxes along the way.

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　　5. Gates of the Arctic National Park and Preserve, Alaska

　　Want remote wilderness? Go to Alaska, then keep heading north into the Brooks Range, and you’ll find Gates of the Arctic, a 13,000-square-mile expanse of mountains and river valleys north of the Arctic Circle. There are no roads in Gates of the Arctic, nor a visitor center or gift shop, nor even established trails. Just herds of caribou, the glow of the northern lights, and several federally designated Wild and Scenic Rivers winding through the tundra.  

　　Best Time to Visit: Hands down, summer has the warmest temps, as well as rivers that are full from snowmelt and a landscape that comes alive as everything from wildflowers to grizzly bears makes the most of the sunshine. There’s plenty of that, too; you’re so far north, you can expect daylight for up to a month at a time in the summer.

　　Signature Adventure: Try, if you can, to see this park from the hull of a boat. Consider paddling the Noatak, a sinuous river that’s carved a broad valley through the Brooks Range. You’d plan for a 10-day canoe-camping trip, with mostly calm water and a few stretches of class II rapids on the 60-mile section inside the park. You’ll float past meadows full of alpine sunflowers and snow buttercups, fish for arctic char, and keep an eye out for grizzlies, wolves, and Dall sheep (guided trips from $8,900).

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　　6. Gateway Arch National Park, Missouri

　　Gateway Arch isn’t like other national parks on this list. It’s an urban park, located in St. Louis, that was originally set aside to commemorate the cultural significance of our country’s push westward. It’s only 91 acres, tucked into the banks of the Mississippi River, and has the 630-foot Gateway Arch as its centerpiece. Fun fact: this is the tallest arch in the U.S. Inside the park are five miles of paved trails for walking and running along the Mississippi.

　　Best Time to Visit: Show up in fall or spring, when the weather is mild and the crowds are minimal.

　　Signature Adventure: Really, ride the tram to the top of the arch. The journey takes you through the structure’s hollow legs and ends at a viewing platform with a panorama of the Mississippi River and its many bridges below. The only catch? The ride will cost you $19.

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　　7. Great Basin National Park, Nevada

　　It takes some effort to reach Great Basin National Park, in eastern Nevada roughly 285 miles north of Las Vegas, but once you’re there, you won’t need to contend with crowds. Only 140,000 people a year venture to Great Basin, compared to 14 million visitors for Great Smoky Mountains National Park in 2023. Yet Great Basin has towering 13,000-foot peaks; groves of shimmering aspen as well as old-growth bristlecone pines, which are believed to be the oldest known tree species in the world; and a fascinating system of caves to explore.

　　Best Time to Visit: Much of the park can be inaccessible during winter, when the 12-mile Wheeler Peak Scenic Drive, which ascends from 6,700 to 10,180 feet in elevation, is unplowed but open to skiers and snowshoers, and there are various other winter closures. So going between late spring and early fall is your best bet. Late summer will give you the best chance for snow-free trails.

　　Wheeler Peak Trail

　　Signature Adventure: The cave tours are popular, but I say hike to the top of 13,063-foot Wheeler Peak, where views of the Great Basin Desert, the only “cold” desert in America—the precipitation comes from snow—stretch in every direction for 100 miles on a clear day. It’s a 6.1-mile out-and-back that gains 3,000 feet, much of which is above tree line, so take it slowly if you’re coming from sea level. Interested in something milder? Hike the 2.7-mile Alpine Lakes Loop, which brings you to the edges of Teresa and Stella Lakes, both pools surrounded by evergreens.

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　　8. Great Smoky Mountains National Park, North Carolina and Tennessee

　　This is the most popular national park in the country, with, as said above, some 14 million visitors annually. Fortunately, there are 500,000 acres of mountains in Great Smoky Mountains National Park for all those people to explore, with more than 900 miles of trail that access 6,000-foot peaks, pristine trout streams, and historic farming valleys.

　　Best Time to Visit: There’s no bad time to hit GSMNP. The foliage goes nuts come fall, winter can bring snow and solitude, and spring is budding with renewed life…but I like summer in the Smokies. Sure, some parts of the park are crowded, but the temperatures are perfect for splashing in the waterfalls and swimming holes.

　　Signature Adventure: Most visitors stick to the scenic Newfound Gap Road and its short nature trails, but I recommend hiking the 11-mile out-and-back Alum Cave Trail up to LeConte Lodge, a backcountry inn on top of the 6,000-foot peak of the same name. Some sections of the trail are so exposed you use cables for safety, and you’ll pass through Alum Cave, a rock overhang with a long-range view into the park. If you can’t score overnight reservations at the lodge, purchase a sack lunch from the kitchen for a picnic in some quiet spot with a view before heading back down to the trailhead.

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　　9. Hot Springs National Park, Arkansas An aerial view shows Hot Springs Bathhouse Row, Hot Springs National Park, Garland County, Arkansas, in summer amid the regions green hills. Video courtesy Arkansas Department of Parks, Heritage and Tourism

　　Forget rugged cliffs or backcountry lakes. Hot Springs National Park protects a small town that was built on top of thermal springs that attracted travelers for centuries before the area ever became a national park. Today, you’ll find two brick bathhouses for soaking your weary muscles and public fountains where you can fill a jug with natural spring water for drinking.

　　Best Time to Visit: The weather in the park is generally mild, so it’s a popular destination year round, but winter feels like the right time to sit in a tub of hot water.

　　Signature Adventure: Can relaxing be an adventure? Who cares? When in Hot Springs National Park, you sit in hot water. The Buckstaff Bathhouse has small private tubs, while the Quapaw Bathhouse has a series of larger, Roman-style pools for group bathing as well. A man-made steam cave captures the radiant heat from the 143-degree water (from $25 per person). You can also hike the trails here and are welcome to bike on any of the paved roads and the Pullman Trail.

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　　10.  Katmai National Park and Preserve, Alaska

　　Katmai National Park is surely best known for its live bear cams, where you can watch massive brown bears fish for salmon from the comfort of your office chair. But this 4-million-acre park in Southern Alaska is more than just an internet sensation; it’s a playground of lakes, rivers, and mountains, with an active volcano.

　　Best Time to Visit: Show up in July when the temps approach 70, and the brown bears are actively hunting for fish.

　　Signature Adventure: Try to get a campsite or lodge room at the float-plane accessible Brooks Camp (make reservations starting January 5, $18 per campsite per night) on the edge of Naknek Lake, and hike the 1.2-mile out and back to Brooks Falls, where the park’s most popular bear cam catches grizzlies poking around the water for salmon. Don’t worry, the hike ends at an overlook a safe distance from the action.

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　　11. Kenai Fjords National Park, Alaska The heart of Kenai Fjords is the Harding Icefield, a 700-square-mile sheet of ice that has shaped Alaska’s Kenai Peninsula by leaving glaciers and carving fjords. Visitors to the park have 600,000 acres of fjords to paddle, many trails to hike, and innumerable icy crevices to explore, with guided climbing and rappelling options available.

　　Best Time to Visit: Technically, Kenai Fjords is open year round, but winters are cold and snowy, and the only way into the park is by fat bike, XC skis, or dogsled. Show up from June through August and the trails are open to hikers, the roads are clear, and wildlife is most visible, as animals actively look for food.

　　Signature Adventure: This is your chance to explore a glacier in all its shrinking glory. A paved road leads to the edge of Exit Glacier, which forms the tail end of the Harding Icefield. From here a system of trails explores the valley carved by the glacier, offering a variety of views. Hike the 8.2-mile out-and-back Harding Icefield Trail, a strenuous climb through cottonwood forests and meadows, then above a tree line ridge that stops at the edge of the massive expanse of ice.

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　　12. Kobuk Valley National Park, Alaska Kobuk Valley is one of the least-visited units of the national-park system (just over 17,000 people made the trip in 2023), but that’s more a reflection of the park’s location north of the Arctic Circle than its landscape, which is a mix of rivers and sand dunes that are populated by a hell of a lot of caribou traveling along the Kobuk River. No roads lead into Kobuk Valley, so most visitors arrive via air taxi. The other option would be a very long paddle in.

　　Best Time to Visit: Shoot for June or July, when you’ll enjoy nearly 24 hours of light every day, blooming wildflowers like the herbaceous locoweed, and temperatures in the mid 60s. Or show up in August when the caribou begin their migration through the park.

　　Signature Adventure: With no established trails or campgrounds inside the park, you need to be self-sufficient. Most people show up to camp in the 25-square-mile Great Kobuk Sand Dunes, or paddle and fish for salmon and whitefish along the 61 miles of the Kobuk River within the park’s borders. Either way, keep an eye out for caribou, which look like lean reindeer.

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　　13. Lake Clark National Park and Preserve, Alaska

　　Much like Kobuk Valley, Lake Clark has no roads leading into the park and is typically accessed by small plane. But make the effort and you’ll see 4 million acres of quintessential Alaskan terrain with 10,000-foot peaks, backcountry lakes, glaciers, and wild rivers, all about 100 miles southwest of Anchorage.

　　Best Time to Visit: It’s Alaska, so summer will give you the longest days and warmest weather of the year. The brown bears are active too, filling up on salmon running up the rivers, so it can be a once-in-a-lifetime thrill seeing them (from a safe distance).

　　Signature Adventure: Catch a float plane to Crescent Lake and spend your time on a boat, fishing for sockeye salmon, which fill the lake in July during their annual migration, or lake trout. Bring your binoculars too, as the lake is a hub for brown-bear activity during the summer.

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　　14. Mammoth Cave National Park, Kentucky Most national parks wow you with what’s above ground, but Mammoth Cave’s secret sauce lies beneath the dirt; the park protects the largest cave system in the world, with more than 400 miles of mapped passages.

　　Best Time to Visit: Mammoth might be the truest year-round park in the system, as the temperature in the caves is a consistent 54 degrees through every season. But visit in the fall and the hardwoods above ground are bursting with color.

　　Signature Adventure: The landscape offers plenty to do above ground, from paddling the Green River to mountain biking the park’s 20 miles of singletrack, but you’re here for the caves. The Historic Cave Tour is the classic introduction, a two-hour guided adventure that hits the biggest rooms and tight channels alike ($24 per person). Or if you’re feeling adventurous, sign up for a Wild Cave Tour and crawl through tight passages that lead to lesser-seen rooms over 5.5 miles of exploration ($79 per person).

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　　15. National Park of American Samoa

　　Looking for something remote and tropical? American Samoa is a collection of seven islands located 2,600 miles south of Hawaii. National Park of American Samoa protects pieces of four of those islands, boasting tropical rainforests, steep peaks, remote beaches, and access to the surrounding ocean and coral reefs.

　　Best Time to Visit: It’s warm year round in American Samoa, but winter can be rainy. The dry season runs from June to September, offering the best chances of good weather for hiking and clear water for snorkeling.

　　Signature Adventure: Tutuila, the largest island of Samoa, is loaded with hiking trails that lead through rainforests to dramatic viewpoints over the coast. If I ever get to go, I’m visiting Ofu Island, which has a remote shoreline with pink sand that has been called the most beautiful beach in the world. The snorkeling is amazing too, as the water is clear, the coral reefs are close to shore and packed with colorful fish, and the area hosts more than 950 species of fish.

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　　16. New River Gorge National Park and Preserve, West Virginia

　　New River Gorge National Park packs an adventurous punch in its svelte 73,000 acres, protecting 53 miles of the class IV New River and the steep, rocky gorge around it. Rock climbing, mountain biking, whitewater rafting…you can do it all inside this relatively small park.

　　Best Time to Visit: Summer brings the warmest weather for rafting, but if you’re looking to climb, show up in the fall when the humidity dissipates, temps drop, and the leaves pop.

　　Signature Adventure: It’s hard to pick just one here, but rafting the New has to top the list. The river drops 750 feet inside the park’s boundaries, unraveling in a series of III-IV wave trains, drops, and big pillows. A number of outfitters run trips, from half-day milder water options to two-day overnight adventures.

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　　17. North Cascades National Park, Washington

　　North Cascades might be close enough to Seattle for a day trip, but this landscape is a world removed from the bustling city, with high alpine terrain full of evergreen forests, craggy peaks, backcountry lakes, and more than 300 glaciers–the largest collection in any park outside of Alaska.

　　Best Time to Visit: Late June to late September has the most user-friendly weather and the best chances for snow-free trails.

　　Signature Adventure: Take on Desolation Peak, a steep 9.4-mile hike from the edge of Ross Lake that passes through meadows toward sweeping views from a historic lookout tower that Jack Kerouac once lived in while working as a fire scout. On the horizon are the craggy, fin-like Hozomeen Peak and a portion of the Ross Lake National Recreation Area.

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　　18. Virgin Islands National Park, Virgin Islands

　　Protecting two-thirds of the island of St. John, Virgin Islands National Park is packed with beaches, lush mountains, and tropical rainforests. Visitors will split their time between water activities, lounging on beaches, and hiking through the hills.

　　Best Time to Visit: Summer can be hot and rainy and fall brings hurricanes, but winter in the Virgin Islands is delightful, with temps in the 80s and minimal rainfall.

　　Signature Adventure: Explore Salomon and Honeymoon Bay, dueling white-sand beaches separated by a rocky point. Snorkelers have colonies of coral reefs teeming with tropical fish to explore. Or go for a swim in Brown Bay, from a beach that’s only accessible by boat or a 1.5-mile hike on Brown Bay Trail.

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　　19. Voyageurs National Park, Minnesota

　　Situated on the Canadian border in Northern Minnesota, the 218,055-acre Voyageurs National Park is known for its series of lakes interconnected by 60 miles of canoe trails. Moose and wolves thrive inside the park, which is also a good spot for seeing the northern lights.

　　Best Time to Visit: Visitor centers and tour operators open in June and the lakes are busiest in the summer, but September brings changing colors and fewer crowds. The season ends quickly, though, and October can feel more like winter than fall.

　　Signature Adventure: People visit Voyageurs to canoe and fish the lakes for walleye and northern pike. The larger lakes can be busy with motorboat traffic, but the smaller interior lakes are linked by a series of marked canoe trails and backcountry campsites. Paddle the 13-mile Chain of Lakes trail, which traverses four small lakes on the Kabetogama Peninsula via small creeks and short portages. Each lake has a campsite, and the park service stages boats for use by those with camping permits.

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　　20. Wind Cave National Park, South Dakota

　　One of the oldest national parks in our system, established in 1903 by Theodore Roosevelt, the 33,000-acre Wind Cave protects a landscape in transition, where the Great Plains give way to the Black Hills. Above ground, the park boasts broad swaths of grassland occupied by herds of bison and elk, but underneath that bounty of wildlife are 143 miles of mapped cave passages.

　　Best time to Visit: Summer is hot and thunderstorms with hail are common, while winter brings snow and sub-freezing temps. Hit Wind Cave in the shoulder seasons (spring or fall) for mild weather and to see active wildlife.

　　Signature Adventure: The only way to explore the caves is on a ranger-led tour. The Natural Entrance tour is a good family-friendly option, as visitors experience the winding opening of the cave system before exploring some of the larger interior passages, known for walls that look like honeycombs. If you want more of an adventure, sign up for the Wild Cave tour, which will have you crawling through smaller, undeveloped passages deep down in the system ($17 per person).

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　　Graham Averill is Outside magazine’s national-parks columnist. Based in Asheville, North Carolina, he is fortunate enough to live within a few hours of three free national parks. He recently wrote about the best hikes in Joshua Tree National Park, his favorite mountain town, and the national park he chose as the most adventurous.