Five US national parks only reached by sea or sky

Road trips to national parks are a classic US travel experience. But for truly "wild" landscapes, venture to these remote protected lands you can only reach via boat or seaplane.

In 2024, a record 331.9 million travellers from around the world descended on sites managed by the US National Park Service. But while the country's national park system was created to help preserve the US' vast wilderness, those driving to explore these famous landscapes may increasingly find themselves braving crowded car parks and dense crowds.

For adventurous travellers hoping to escape the masses, there's an intriguing alternative: venturing to one of the few US national parks that are only accessible by boat or seaplane.

"Arriving by air or sea makes you acutely aware that you're entering landscapes that operate on their own terms," says Crystal Jones, a senior tour leader at the travel outfitter Intrepid. "The challenge of reaching these parks is part of their power. They reward travellers with something increasingly rare: a true sense of wilderness."

From sun-soaked islands basking in the Caribbean Sea to a vast tundra landscape located above the Arctic Circle, here are five US national parks that road-trippers can't reach.

Channel Islands National Park, California

Often called "the Galapagos Islands of North America", Channel Islands National Park is made up of five volcanic islands located 20 to 70 miles off the southern California coast and is home to dramatic peaks, coves and hiking trails – as well as 145 plant and animal species that live nowhere else. The islands are only accessible via ferry or private boat from Ventura or Oxnard Harbors.

"It can feel crowded when you get off the boat, but within five minutes you can be alone," says Russell Galipeau, Channel Islands National Park's former superintendent. "Many want to experience solitude, and that's what you'll find here." In fact, since the islands are car-free, the only way to navigate them is on foot, by kayak or by private boat.

One of the oldest-known human remains in North America was found in the national park, leading some experts to believe that the Channel Islands were a stopping ground during the earliest human migration from Asia to the Americas. Find out more here.

Sea kayaking is a favourite activity here, and Santa Cruz Island (especially Scorpion Beach, located on the isle's north-east coast) is a popular paddling spot. Since the windswept islands have few beaches on which to land, Galipeau notes that it's important for visitors to understand the currents to avoid being swept away. Off the islands, visitors can go whale watching with Island Packers to spot some of the more-than-20 dolphin and whale species living nearby, including bottlenose dolphins and humpback, sperm, pilot and orca whales.

Want to explore below the surface? The Santa Barbara Adventure Company rents snorkel gear and offers guided tours of the islands' kelp forests and marine life. If you want to stay overnight, there are campgrounds, but you need to reserve in advance. (Tip: bring all your supplies and gear as there are no services in the national park.)

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Located north of the Arctic Circle and 250 miles north-west of Fairbanks, Gates Of The Arctic National Park & Preserve is the US' northernmost national park. There are no roads, trails or campsites here, and the only way to experience it is via air taxi or by hiking in. The park consists of 8.4 million acres of vast, untouched tundra and boreal forest. But what it lacks in services and facilities, it makes up for in wild rivers, lakes and rugged peaks within the central Brooks Mountain Range. The National Park Service notes that all visitors should be proficient in outdoor survival skills and emergency situations.

Gates of the Arctic National Park & Preserve is the least-visited US national park. Fewer than 12,000 people visit it most years.

According to Cory Lawrence, CEO and president of Off the Beaten Path, a tour company that leads chartered trips to some of the US's most far-flung national parks, part of the magic of the area isn't just experiencing its raw, Arctic landscape on the ground, but flying in. "You're seeing these places from the air, which is really spectacular," Lawrence said. He explained that lucky, eagle-eyed travellers may see moose, Dall sheep, wolves, wolverines and black and grizzly bears from the plane.

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Set 70 miles west of Key West in the Caribbean Sea, Dry Tortugas National Park covers 100 square miles of ocean – and 99% of its protected area is actually located underwater. The park is home to the third-largest barrier reef in the world, so it's no surprise that these seven small islands are renowned for their snorkelling and diving. Above the surface, the sprawling, 19th-Century Fort Jefferson military base appears to float on the turquoise sea and once housed one of the men who conspired to kill US president Abraham Lincoln.

"It's not every day that you get a physical remnant of a civil war, a presidential assassination link, bird watching, sea turtles [and] marine biodiversity all in one place," says Thalia Toha, a geographer and architectural historian, who recently visited. Visitors can arrive via a private boat, charter or ferry from Key West, or they can board a seaplane from Key West International Airport.

Dry Tortugas National Park is one of the few places along the US' East Coast where you can see the Milky Way without a telescope. Find out more here.

Toha loved snorkelling at Garden Key, where corals grow near the islands' former piers and warehouses built in the 19th Century by the US Navy, creating dense fish habitat. She also recommends Loggerhead Key, whose vibrant reefs attract blue tang, barracuda and turtles. Elsewhere, travellers can dive to the famous Windjammer Avanti, an iron-hull ship that sank in 1907. "The shipwreck is noteworthy because it's fairly well preserved," says Toha, noting that at just 22ft deep, it's fairly accessible.

Staying overnight in a campground is an option, but visitors must bring all their own food, water and gear. "One of the benefits of camping is at night you see the stars in a different way – a glassy sea horizon reflecting the stars. It's almost like a dream," she says.

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This remote archipelago of more than 450 islands in Lake Superior is only open to the public from mid-April through October. Designated as a Unesco Biosphere Reserve, this forested wilderness invites travellers to hike through forests, scuba dive to shipwrecks, fish, canoe or kayak.

Isle Royale is one of the world's largest lake islands and was settled by Native Americans more than 8,000 years ago. Find out more here.

Visitors can board the ferry in Grand Portage or Copper Harbour and pay a daily $7 (£5.20) park entry fee. Overnight guests should book accommodation in advance at Rock Harbor Lodge or Windigo Camper Cabins, or pitch a tent at one of the 36 first-come, first-served campgrounds. "Day-trip exploration is possible, but requires good coordination with ferry or seaplane transport," says Lawerence, who offers customised guided trips to the park.

Visitors can rent kayaks and canoes at the Windigo Camp Store or the Rock Harbor Marina and Lodge and paddle in Washington Creek for a prime opportunity to spot moose, beavers and otters. Elsewhere, the Greenstone Ridge Trail, which stretches more than 40 miles from one side of the park to the other, or the Minong Ridge Trail, are two of the most popular (and challenging) hiking trails on the island.

Katmai National Park & Preserve, Alaska

Encompassing some four million acres, Katmai National Park & Preserve is an expansive wilderness of rivers, streams and the scarred Valley of Ten Thousand Smokes, where the largest volcanic eruption of the 20th Century occurred. While the park is larger than Connecticut and home to narrow gorges, extinct fumaroles and mountain-fringed lakes, the main draw is the roughly 2,200 brown bears that live here. In fact, the multiple viewing platforms at Brooks Camp are one of the best places to see brown bears in the wild – especially during the summer salmon run.

Ever heard of Fat Bear Week? The annual competition, orgnanised by Katmai's park rangers, lets fans around the world vote for their favourite chunky bears. This past year's winner weighed in at more than 500kg. Find out more here.

Since visitors can only arrive by seaplane or boat, getting here requires some planning – but those who have made the journey say it's worth it. "Seeing [Katmai] in person – after arriving by plane to a place with no roads in or out – adds a depth that television can't capture, says Jones.

For those wanting to linger, visitors can fish, take a "flightseeing" tour or stay at lodges at Brooks Camp. Whether bedding down in a cabin or campground, travellers can hike historic routes such as Katmai Pass or climb Observation Mountain for sweeping views across the Katmai River valley and gorge below.

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