Cayo Costa State PArk, Floridaa

An aerial view of Cayo Costa State Park (©James Randklev/Getty Images)

Some of the most beautiful and secluded beaches in the United States aren't necessarily secret; they're just hard to reach in one way or another. An island beach that requires a ferry ride; a long strand accessible only by four-wheel drive; a sandbar that disappears at high tide; a remote swath of sand and sea that lies at the end of a substantial hike over perilous terrain.

"People don't understand what's happening with the ocean, how we could impact something so vast."

Stephanie Wear, The Nature Conservancy

And then there are the human-made obstacles. "We're seeing more and more locked gates" on roads and trails that had provided public access to beaches, says Angela Howe, legal director of the Surfrider Foundation. The foundation is fighting to reopen access to Martin's Beach in Half Moon Bay, Calif., where a private landowner has blocked a footpath long used by the public. "We're scoping out litigation, raising public awareness and getting the story out in the media."

It may seem counterintuitive at first, but many conservationists do want us--at least just a few of us--to visit hard-to-reach beaches where the public is allowed, to know and value them. "People don't understand what's happening with the ocean, how we could impact something so vast. I want people to go to the beach and be inspired," says Stephanie Wear, coral reef director for The Nature Conservancy.

So without further ado, and in (subjective) order of difficulty starting with the easiest, here's a rundown of some of our favorite beaches that play hard to get.

Cayo Costa State Park, Florida
Next time you're in Bokeelia, Fla. (on the north shore of Pine Island, west of Fort Myers), stroll to the Jug Creek Marina and take a boat to Cayo Costa State Park, accessible only by small ferry or private boat. There you'll find nine miles of beaches, snorkeling, fishing and, if you're lucky, a manatee or three. Stay over if you'd like. "There's rustic camping, primitive cabins and that heritage feel of Florida," says Julie Brashears Wraithmell, director of wildlife conservation for Audubon Florida. "Sea turtles nest on the beach by starlight. You'll have your getaway experience without causing harm." Is Cayo Costa too easy to call "hard to get"? Maybe, but we're just getting started.

Currituck National Wildlife Refuge, Outer Banks, North Carolina

Currituck National Wildlife Refuge, Outer Banks, North Carolina (©Ocean/Corbis)

Currituck National Wildlife Refuge,
Outer Banks, North Carolina

Where in the world is there a species of mammal less welcomed on the beach by conservationists than Homo sapiens? Just north of Corolla, N.C., where the managers of the Currituck National Wildlife Refuge would rather not see so many feral horses, which, as a nonnative species, trample the vegetation and upset the ecosystem. To get to Currituck, you either need a four-wheel-drive vehicle or you must do as the horses do and hoof it for three-quarters of a mile from the end of the road north of Corolla to the refuge boundary. Your reward will be miles of pristine barrier-island beach, woodlands, wetlands and brush, together with the birds, reptiles and those controversial horses (they do draw tourist money). Visit between late fall and early spring and you'll likely have the place to yourself.

Padre Island National Seashore, Texas

Padre Island National Seashore, North Island (©Corpus Christi CVB)

Padre Island National Seashore,
Corpus Christi, Texas

Seventy miles long, majestic Padre Island National Seashore claims the longest undeveloped barrier beach in the world. A complex of sand, marsh, dunes and lagoon, most of Padre Island is accessible only by four-wheel-drive vehicle - unless you're foolish enough to try your Camaro in the sand. Speaking of which, the National Park Service should win an award for this understatement: "Keep moving in deep sand. It may be difficult to pull out if you stop." Try your luck and you might see shorebirds, marsh birds, raptors and songbirds; 45 percent of all North American avian species have been spotted here, along with about half of the Kemp's ridley sea-turtle nests found along the entire Texas coast. On your way out, just watch out for turtle nests and the occasional gun-toting driver - licensed firearms are permitted on all Texas beaches, and all Texas beaches are public highways.

Morrow Bay Sand Spit, California

View of Morro Bay across the sand spit at Montana de Oro State Park (©Richard Wong/Alamy)

Morro Bay Sand Spit,
Montana de Oro State Park, California

A thin strand with dunes reaching 10 stories into the sky - and waters treacherous enough to make swimming foolish - make for an outing that's just challenge enough to deter casual beachgoers. "From my office nearby, I love to go to Morro Bay Sand Spit," says Andrea Jones, director of the Important Bird Areas Program for Audubon California. "You take a half-mile trail on a pretty steep slope to the sand spit, where you see a few hikers and birdwatchers and a lot of birds, with Morro Bay on one side and the open Pacific on the other." What paints gold on 1,347-foot Valencia Peak in this 12-square-mile seaside Eden? Spring poppies and buttercups by the millions.

Thousand Steps Beach, Santa Barbara, Calif.

Thousand Steps Beach, Santa Barbara, Calif. (Courtesy of the Santa Barbara Conference & Visitors Bureau and Film Commission/Greg Peterson)

Thousand Steps Beach,
Santa Barbara, Calif.

The folks who picked the English name for Santa Barbara's Camino Al Mar came up with a simple yet effective way to reduce people traffic at this beach: Pick a nickname--Thousand Steps--that exaggerates the downs and ups of the access stairway by a factor of six. Yes, it's actually a mere 150 footsteps down steep, mossy and often wet stone steps to a rock-strewn water's edge that connects at low tide with miles of mostly flat sand north and south. Under tree-topped cliffs you'll see gulls, pelicans and--out to sea--an occasional pod of dolphins enjoying each others' intelligence and the paucity of human folly. Find this staircase to beach heaven near the corner of Santa Cruz Boulevard and Shoreline Drive in Santa Barbara.

Barred Island, Maine

The inter-tidal zone on Maine's Barred Island, Deer Isle (©Thomas R. Fletcher/Alamy)

Barred Island,
Deer Isle, Maine

Barred Island is a Nature Conservancy property featuring an enchanting stroll through a ferny, mossy forest to the bar, a diminutive, 100-yard-long hump of sand that connects it to Deer Isle, the mainland, relatively speaking, in this land where even the islands have satellite islands. Diminutive, as in the bar diminishes to zero on the way to high tide. The hard part? Fighting off the mosquitoes along the wooded trail, remembering to arrive near low tide, and somehow getting the kids to put up with what is basically a one-mile walk in the park. Barred Island, administered by the Island Heritage Trust, is in Deer Isle on midcoast Maine's Blue Hill peninsula.

Red Sand Beach, Hawaii

Red Sand Beach, Hawaii (©Monica & Michael Sweet/Getty Images)

Red Sand Beach, Maui, Hawaii
This is one of the smallest hard-to-reach beaches on our list, the most colorful, and an exotic gem even in Hawaii, which certainly has its share of rare sights where land meets sea. Red Sand Beach, which gets it name from the crumbled cinder cone from which its sand was formed, nestles in a cozy cove south of Hana Bay on the east coast of Maui. The surreally polychromatic scene: blackish red sand, sapphire sea, black lava wall blocking the breakers - with emerald-green ironwood trees all around. How does this singular strand play hard to get? The only access is by a short but narrow, steep and slippery footpath down the cinder cone. Wear your best treads.

Isaac's Bay Beach, in the Virgin Islands

Isaac's Bay Beach, in the Virgin Islands. (© John Wooldridge)

Isaac's Bay Beach,
St. Croix, U.S. Virgin Islands

"My favorite beach is Isaac's Bay Beach on the east end of St. Croix," says Wear of The Nature Conservancy. "You have to hike over rocky cliffs and down into a valley." During this moderately challenging hike, don't forget to lift your eyes and take in the stunning ocean views from the high points along the trail. "Then you get to a sandy strip of beach that's pretty much your own." There are coral reefs just beyond the surf zone with good snorkeling, though the surf is rough at times, reducing visibility and making it a challenge not to exchange injuries with the coral. Remember that the hike back to the parking lot is uphill; bring extra water.

Halape, Hawaii Volcanoes National Park, Hawaii

Keauhou Beach in Hawaii Volcanoes National Park (©NPS Photo/Jay Robinson)

Keauhou, Halape
Hawaii Volcanoes National Park, Hawaii

OK, so you think you're up for the big kahuna, our hardest-to-reach beach with some of the most gorgeous ocean waters in the world? It's Halape, in Hawaii Volcanoes National Park, 30 miles from Hilo on the island of Hawaii. In our recent conversation with a park ranger there, he ran out of fingers, then toes, naming reasons to think carefully before undertaking an outing to Halape, which requires an overnight by the beach for all but the most intrepid and well-hydrated hikers.

Here are just a few sunburned bits of what Adrian Boone had to say about this anything-but-a-walk-in-the-park: "Leaving from Chaining Craters Road, you're going to walk from an elevation of 2,600 down to sea level. You start from the middle of the 1969-1974 lava flow, walk through barren black lava, then forest, down two or three steep cliffs with loose footing, through grasslands deforested by goats and pigs. You may suck in some 'vog'--fumes from volcano smog--and encounter paper wasps and, at the campsite, cockroaches, centipedes and scorpions."

If you do make it to the water, beware of stepping on sharp reef or sea urchins; "those cuts take a long time to heal and might get infected," Boone writes. Oh, and don't forget: The hard part is the return trip, with a half-mile vertical gain back to your car. Your reward? Some serious solitude and possible sightings of ruddy turnstones, nesting hawksbill sea turtles--and those extraterrestrial blue waters.

John Rossheim is a frequent MSN contributor.