To my left, ominous gray swells roll in from the horizon and slam into the jetty. To my right, the massive, white-capped Columbia River rushes seaward. Where the two meet, at the end of this jetty, is an insane crosshatch of waves that can reach 20 feet – the Columbia River Bar, foggy 200 days a year, with blasting winds and some of the worst wave conditions in the world. This is also, roughly, the start of the Oregon Coast Trail, which unfolds to the south over 363 miles of perfect beaches, crystal-clear rivers, and rocky headlands, and through deep forest: a wild and pristine corridor between the moody woods of the Coast Range and the crashing Pacific.

It's one of the most beautiful places on Earth – and it belongs to you. In the U.S., where most of the shoreline is privately owned, Oregon stands out for its unrivaled beach access: Every square inch of the coast, from the lowest tidemark up to the line of vegetation, is free and open to everyone, with ubiquitous state parks that offer easy entrance to trails and beaches. Oregon governor Oswald West first dedicated the beaches to the people of Oregon in 1913 (he had the coast declared a public highway, effectively blocking development), a legacy that was enshrined into law with 1967's Oregon Beach Bill.

Oregon's beaches may not conjure hints of coconut oil and visions of palm trees – the coast stays cool and misty most of the year, and the water is chilly (subarctic currents keep temperatures in the 50s). But it's a coast you can actually explore: by surfboard, by kayak, by bike, by trail. And when you're ready to return to civilization, you can drift inland to fishing villages and old pioneer towns for wild salmon, ultralocal craft beers, Dungeness crab, and fresh Pacific oysters, hauled straight from the water and shucked on the spot. Over five days, I worked my way south, on coastal trails and Highway 101, from the Columbia River down to the California line.

In the fall of 1805, Lewis and Clark arrived on Oregon's northern coast ("Ocian in view! O! the joy") and set up camp about five miles from where I've been standing, on the docks of Astoria, watching leviathan tankers head to sea. Fur traders put down roots here in 1811, and it still has the pleasingly seedy feel of an old wharf town, a legacy of its 19th-century harvest booms: It's been a fur-trading hub, a whaling capital, a fishing and canning empire – an estimated 10 to 16 million salmon once returned to the Columbia here each year. Astoria's latest boom is reinventing the past: On my first night, I dine at the Fort George Brewery, where Astorians craft lager and ales in a renovated auto garage; I sleep at the Cannery Pier Hotel, which rests on the pilings of a historic, 600-foot pier; for breakfast, I eat boat-fresh albacore tuna from Bowpicker Fish & Chips, a fry shack hidden in an old trawler, before heading down the coast.

Where Lewis and Clark once hunted for elk and traded with coastal tribes is now a string of pleasant and popular beach towns, all within a couple of hours of Portland. I make the full circuit on my second day, alternately hiking and driving (still permitted on some stretches of beach) past the fine, faded mansions of Gearhart and on to its antipode, Seaside, the Coney Island of Oregon, where calliope music follows me through the arcade maze, the sea breezes are laced with the smell of cotton candy, and you can dress up like a 19th-century pioneer and have your portrait taken. The Lewis and Clark Trail ends here, just off the old beach promenade: The friends, cast in bronze, gaze out over the water, their backs turned on the arcades and taffy vendors.

I forge ahead, over Tillamook Head, through temperate rain forest that ends 1,000 feet above the sea, and on to bustling Cannon Beach, anchored by Haystack Rock, a 235-foot sea stack ringed at low tide by pools of starfish and anemone. But my favorite beach this day is a mellow surf spot a bit farther down, Short Sand Beach, near Manzanita. Toward Smuggler Cove – once beloved by pirates, according to lore – surfers carry their boards through a Jurassic scene dense with ferns and moss-covered trees and down to a hidden beach: a deep arc of sand, cut through by a cold creek, surfers in half-peeled wetsuits hunched around beach fires.

Along the sinuous central coast, Highway 101 snakes inland again and again, from Tillamook Bay (home of the cheddar giant) to Depoe Bay (smallest navigable harbor in the world), Newport's Yaquina Bay (home to Rogue Ales), Coos Bay (biggest city on the coast, with almost 16,000 people), and innumerable smaller inlets, edged with roadside oyster and crab shacks. Coastal trails meander onto the dramatic headlands that loom hundreds of feet over the Pacific here. Summiting the steep, wildflower-choked trail to Cape Perpetua feels like stepping from the jungle directly into near space, with vertiginous views that seem to take in the curvature of the Earth.

As you head south, through towns that once thrived on timber, salmon, and gold, frontier architecture takes over: Old West sets as if from gunslinger movies dropped incongruously at the beach. One of the most fun is Florence, a mix of rugged history and new refinement. (Great dinner: razor clams and Gold Beach Lager at Waterfront Depot, housed in a century-old train station overlooking the Siuslaw River.) Florence is also the start of the Oregon Dunes National Recreation Area – 40-plus miles of Saharan-size coastal dunes, the biggest in the U.S. It's strange to think of a pile of sand as something ancient and alive, but these massive dunes (some more than 500 feet high) have been migrating along the coast for millions of years, subsuming forests, shifting rivers, and burying parts of towns.

Most people come here to race ATVs and dune buggies (or to fish the freshwater lakes hidden among the dunes), but in the quieter sections, you can explore for miles – climbing high, wild slopes; crossing "tree islands," pockets of old wilderness cut off by the sea of sand; and following trails to supremely remote and rugged beaches. Just beyond a nearly vertical dune, a ranger stands, looking incredibly happy, next to a tableful of skulls: deer, coyote, fox, bear. (All the Oregon park rangers I meet emanate the serene joy of enlightened monks.) Pointing to the biggest skull, he says that black bears like to "vacation here, on the tree islands" – roving from one to the next, leaving big, soft tracks in the sand. I end the day by jumping from one of the dunes right into a clear, blue lake – a paradise of sudden contrasts – and pitch my tent at Sunset Bay.

The southern coast is Oregon's wildest, warmest, and most remote: From the mountain lions roaming the Coast Range, to elk grazing beside sea-bound creeks, to plovers nesting along the beach, and straight down into the Pacific, where seals bob in the waves, the wilderness feels continuous here in a rare way. This area offers two of the best long, uninterrupted hikes on the coast: the 13-mile Samuel H. Boardman State Scenic Corridor and the 29 miles of the Oregon Coast Trail from Bandon to Port Orford, where you might easily go hours without seeing another soul, and where you can set up camp for the night, (ideally) grill fresh fish over a beach fire, and drift off to the sound of waves crashing.

But the towns are great, too. Bandon's now most famous for golf: The Bandon Dunes Golf Resort, a few miles outside of town, is ranked among the world's best for its seaside links course, ranged by wild deer and by golfers who arrive from all over the globe by Learjet. At nearby Floras Lake, everything is electrified by the wind – meadows shimmer, trees shake, a ghostly layer of sand buzzes across the trail. A lone kitesurfer speeds toward the Pacific (separated from the lake by a stretch of sand and beach grass), launching high enough to glimpse the sea.

The Rogue River (one of the eight original "wild and scenic" rivers set aside by Congress for protection) hits the Pacific at Gold Beach. The town's boom lasted just a couple of seasons before miners drifted upriver in search of new veins, but it remains an adventure destination: Class V rapids, world-famous salmon runs, and some of the wildest territory left in the U.S.

And then, all too quickly, I reach the last of the coastal towns, Brookings. This is where California conditions start to prevail – sunnier days and warmer waters, one of the few beaches in Oregon where swimmers regularly leap into the waves. California is just six miles from here – I drive across the border and pull into the first beach park: A grackle watches me from atop a broken-down RV, a bandanna blows across a buckled parking lot. It's like a scene out of 'The Walking Dead.' I speed north, back to Oregon's redwoods and the high, green refuge of untouched wilderness.