Over a stone bridge spanning whitewater, up a muddy path, and through a heather pasture where sheep nurse their lambs, we reach the base of a knife-edge ridge in Donegal. Known as Sturrall Headland, it juts 2,624 feet into the North Atlantic and drops 590 feet into the sea. From the landward side, the route to the top looks like a T. rex spine. It’s unstable, so Iain Miller, a Scottish expat and my guide, descends the precipitous scree to the bottom of a near vertical quartz wall on the seaward side, where our climbing party of three ropes up. If I slip before I tie in, it’s a bloody bounce to the rocky shoreline a few hundred feet below.

“You hear that noise? That’s when I know I’m home,” says Miller, referring to the crash of the waves as he leads the first section, a 20-foot short vertical face. “The water has to be there. If you’re not climbing over the sea, something’s missing.”

Before Miller, 46, moved to Ireland in 2005, he spent almost 20 years at sea as a ship’s engineer. He’s scouted every country with a coastline and knows that Donegal’s is rare.

“I’m all about at-home epics,” he shouts at us from above. “Twenty people max have stood on the top of this ridge, and I’ve traveled less than two hours from my house. I can do this and be home in time for tea and medals!”

It takes an obsessive athlete to engage with the fierce coastline in Ireland’s far northwest corner. Seaside cliffs stretch on for miles, often there are four seasons in a day, and ocean temperatures average 48 degrees. Climbers, surfers, kayakers, windsurfers, and sailors need technical skills, extensive knowledge of tides, and the patience to wait out lethal conditions.

With a powerful six-foot build and a diet consisting almost entirely of spicy Bombay Bad Boy Pot Noodles, Miller isn’t a wiry climber. He is, however, skilled in undertaking dangerous expeditions, honed by a childhood spent hill walking and climbing in Scotland and a career handling power outages and engine-room fires on massive container ships.

After he moved to Donegal, Miller set out on a quixotic mission that the locals thought was nuts: to climb 100 sea stacks off the county’s 800-plus-mile coastline. He has climbed 99 so far, ranging in height from 40 to 500 feet and in difficulty from 5.3 (easy) to 5.10 (very challenging). He is such a man possessed that the first four dates with his Irish girlfriend, Caoimhe Gleeson, were sea-stack climbs. On the last summit they reached together, Gleeson told him, “That’s fucking it!” They now have a two-year-old son.

I met Miller a couple of years ago at a conference in Ireland. His one-man guiding company, Unique Ascent, led our small group on a pathless ramble to a cliff overlooking the North Atlantic. Five hundred feet below sat a line of sea stacks, all of which Miller confessed to climbing. “I don’t even take a cell phone when I climb them,” he told me. “I prefer to be totally, utterly alone.”

Miller knows this coast better than anyone. In 2015, he guided more than 150 people to 100 summits. He has meticulously documented, photographed, and YouTubed almost every climb, and has written 27 free, downloadable guides to Donegal—as well as a hardcover book—all of which are available through the Unique Ascent website. I was so intrigued by the terrain that I booked Miller as my guide for a week last April to find out what else was in Donegal.

“In the UK, this would be a scramble,” says Miller’s other client with us today, Hendrik Morkel, a German-Dutch climber, referring to Sturrall Ridge. Morkel, who has the chiseled features of a 19th-century explorer, had heard of the elusive sea-stack climber, e-mailed him in advance, and timed his hiking trip along the Irish portion of the International Appalachian Trail—a 74-mile route that starts in the Donegal village of Bunglass—so he could meet up with us.

When we reach the 100-foot knife-edge traverse to the summit, the wind is gusting at 30 miles per hour. Miller short-ropes us from behind in case we trip or blow off. At the top, we have a view northeast to a jagged shoreline sprouting staggering sea stacks like the 72-foot-high Devil’s Penis, so named because it sits erect and foreboding in a cove of angry-looking froth. To the south is Chaos, Miller’s last unclimbed stack. He named it that because of the imposing stature. It has eluded him for nine years and is so remote that it requires perfect conditions to paddle the half-mile to its base.

“Nobody even knows Chaos exists,” says Miller as he points out the intimidating 200-foot-tall mass. “But it’s a big deal to me, because it’s the last one.”

The odds aren’t in favor of Miller’s plan to climb it tomorrow, with the forecast calling for gusting winds and 16-foot swells. “If I don’t get it done this week, it’s neither up nor down,” he says cheerfully. “As long as no one gets killed, then the day’s a success.”

The first time I saw Donegal, I couldn’t believe that a landscape in the European Union could still be so raw and wild. The county is nearly 1,900 square miles but has only 161,000 residents in its 47 villages and sees just 6 percent of Ireland’s almost nine million annual tourists. Beyond the villages, where the same families have lived for centuries, are heather-covered bogs, quartz and granite cliffs, the Derryveagh mountain range—which rises to 2,467-foot Mount Errigal—and empty white-sand beaches lined with tropical-looking cabbage palms. The topography is reminiscent of Tasmania or the Falkland Islands, but Donegal is accessible via an hour-long flight from Dublin.

Surf breaks south of Donegal rival Hawaii’s in size but see far fewer surfers, likely because the water is so cold. Sea kayakers have a North Atlantic playground, paddling between the eight major islands off the county’s coast, and hikers have the Irish portion of the International Appalachian Trail, which traverses 1,972-foot Slieve League, one of the highest sea cliffs in Europe. Farther inland, road cycling and mountain biking are gaining traction.

As legend has it, Donegal is where, in the fifth century, Christ showed Saint Patrick a cave with visions of hell. During the four-year Great Famine that ended in 1849, the county lost an estimated 40,000 residents to emigration or starvation. Its entire eastern border is Northern Ireland, while to the south its border with the rest of the Republic of Ireland is about ten miles long. During the Troubles—the 30-year conflict between Unionists and Republicans in Northern Ireland that ended in 1998—parts of Donegal were strongholds for nationalist paramilitary groups like the Irish Republican Army and Sinn Féin, the century-old party that promotes economic and political separation from England. The fastest way to reach Donegal from Dublin by car passes through Northern Ireland, and military roadblocks were set up in border towns to ensure that vehicles wouldn’t haul in explosives.

“Government investment was minuscule in Donegal because it was too close to the border violence,” Gleeson told me. In addition to being Miller’s partner, she’s also a mediator for the Irish government. “By the late 1990s, it got better, but then the crash of 2008 hit. It’s really difficult to make a living here. Donegal is mostly rock.”

Today, tensions with Northern Ireland have diminished to the point that there’s no longer a physical border between Northern Ireland and Donegal, and Belfasters have long frequented beach towns like Dunfanaghy. Beyond tourism, sheep farming and fishing have historically been the mainstays of the Donegal economy, but decades of overfishing and resulting quota reductions by the EU have drastically shrunk the industry. According to a 2013 report published by Ireland’s Central Statistics Office, Donegal residents have the lowest disposable income, just under $18,000 per year, in Ireland.

But the more people I meet, the more I hear stories of prodigal sons and daughters returning home. Roland Purcell, the owner of Port Donegal Cottage, an artfully renovated farmhouse on the edge of the sea where we stayed the night after our Sturrall Ridge climb, is Irish, but he was educated in England. He spent the past few decades in Tanzania and Kenya, where he founded a few safari camps and hosted guests like Bill Gates at his remote chimpanzee camp on Lake Tanganyika.

“My father bought this place back in the 1960s as a ruin for 300 pounds and a bottle of whiskey,” Purcell told us while smoking a hand-rolled cigarette before dinner. “We used to take baths in the waterfall in the river.” Since then, Purcell has insulated the roof with sheep’s wool and added solar panels, two bathrooms, a kitchen, and hot water heated by the woodstove. The result is an explorer’s haven filled with maps of the world, fly-fishing rods, and African and Irish sheepskin rugs.

“Port has always been an emotional investment for me, not commercial,” he says. “Donegal has this wild west thing. What this country needs to recognize is that the area has way more value in wilderness than in sheep farming.”

Bartley Brennan, the mustached brother of Donegal’s most famous citizen, the singer Enya, never left. He took over his father’s bar, Leo’s Tavern, a cavernous establishment on a windy road in the village of Meenaleck.

“I can’t sing,” he tells me. “I’m the only one they left behind.” He’s referring to his siblings and two uncles, who formed the band Clannad, and his world-famous sister, who now lives in Dublin and returns for the occasional jam session at the tavern. The pub, which is filled with AC Milan and Celtic FC soccer jerseys and glamour shots of famous musicians, is empty save for the four regulars bellied up to the bar. They’re a talkative, multigenerational mix, from a bricklayer to two wizened souls who have probably been sitting on these same stools for half a century. “We’ve had fantastic nights here,” says Brennan. “U2 played here, but one local guy, Frank, didn’t know who the hell Bono was.”

I’m here to meet Donegal county councilor Micheál Cholm, who was born in the village of Ranafast, ten minutes from the sea. He recently moved back from Dublin so his children could grow up speaking Gaelic. He’s a regular at Leo’s. He’s also a socialist Republican who left Sinn Féin eight years ago because he was uncomfortable with how far it was moving to the right.

“Donegal has been very isolated, with huge poverty,” he told me as we sipped creamy Guinnesses by the fire. “That’s why two of my aunts were jailed for bombing England during the Troubles, for the freedom of Ireland.”

But Cholm sees potential in the wilderness. He’s trying to secure funds to build six one-room cottages in Ranafast for visiting writers and artists.

“We don’t have a shop or a post office, but we’re on the coast and it’s beautiful,” he says. “Locals can benefit from that.”

Traditionally, the tourists who do come are mostly intrepid Canadians and Americans or Irish Americans with family connections. Donegal’s even under the radar for most climbers. Which leaves it all to Miller and me—for now.

Like most North Atlantic islanders, Miller always keeps his eye on the weather—he checks it up to 50 times a day—to determine the best plan of action. One morning, when the sun was out and the risk of hypothermia was minimal, he decided it was a good time to get in the water.

Epic breaks like the Unfound, which draws Irish surfers Peter Conroy and Ollie O Flaherty, are located somewhere between Bundoran, the southernmost town in Donegal, and Mullaghmore Head, farther south in County Sligo. In northern Donegal, around Dunfanaghy, there are five beaches within a half-hour’s drive that are easy to get to and offer waves for mere mortals.

I spent a few hours in a five-millimeter wetsuit surfing off Marble Hill Beach, a protected mile-long half-moon just east of the resort town of Dunfanaghy. If you can brave the water temperature and embrace the dusting of snow on 2,185-foot Muckish mountain in the distance, Marble Hill is perfect for stress-free surfing, with its shallow, sandy-bottomed beach break and consistent four-foot waves. For a late-April morning, there’s a lot of action. About a dozen surfers play in the mile-long surf, and Range Rovers and Audis topped with sea and surf kayaks are lined up outside the Shack, a coffee shop in an entrepreneurial young couple’s backyard.

The water’s cold but the sun is warm, and after the initial shock I feel an adrenaline rush of joy. I’m surfing in the midst of an Irish springtime, and it’s awesome. My instructor, Alex Dixon, from Jaws Watersports in Dunfanaghy, is an expat from England’s Lake District. “I came to Ireland just for the craic,” he says, using a catchall Gaelic term that mostly means “good times.” “But it’s the landscape that keeps me here. It’s so much more peaceful. I wouldn’t go back to England.”

After surfing, Miller and I drive an hour up to a barren mountain pass above 62-square-mile Glenveagh National Park, where we meet Dean Bennett, another British expat and an avid mountain biker. We bomb a few miles of doubletrack, deep into a granite canyon, to the shore of Lough Veagh, and through a moss-covered oak forest to the gates of Glenveagh Castle, a onetime hideaway for stars like Marilyn Monroe and Charlie Chaplin, built in 1873.

As we pedal back up the canyon, scanning the skies for golden eagles, Bennett explains the latent mountain-biking scene in Donegal.

“Everything here is very slow moving,” he says. “When I first came here in the eighties, there was no biking at all. Now there are road rides and a mountain-bike club.”

For world-class riding, he tells me, I need to go south to the county of Sligo, where a coalition is securing funding for the Coolaney National Mountain Bike Centre, which will feature 47 miles of purpose-built singletrack. The park’s date of completion is a few years off and depends on funding, but at the moment I’m thrilled that there’s still a place on earth where mountain bikers don’t care if they’re riding state-of-the-art carbon steeds on custom-bermed trails. When I apologize to Bennett for making him ride with me through sporadic rain showers, he gives me a quizzical look and says, “I don’t do things unless I know it’s going to be fun.”

Even when the skies smudge and the rain persists for days, nobody gets bent out of shape. “The weather is never too hot, never too cold, just constantly damp,” says Miller. “We know its going to rain and it won’t rain forever.”

That night I stay at Danny Minnie’s Country House, a Spanish-villa-style, family-run inn and restaurant in the village of Annagry. On Saturday nights, there are five chefs in the kitchen to serve as many as 120 guests, who drive from as far as Northern Ireland for dinner. The specialty is Donegal lamb with a rosemary, garlic, and honey sauce, followed by brioche-bread-and-butter pudding with stewed apples and rum. It’s a mouth-watering contrast to Miller’s noodle diet.

The next day, we take a ferry out to Tory Island, a 2.5-mile-long piece of rock seven miles off the mainland, to get a sense of the Old World. Windswept and barren, Tory Island has been inhabited for 3,000 years. The fishing community has diminished fourfold since its height of 650 residents in 1900, but Tory still has a skeletal infrastructure, with one primary school, one store, one hotel, one guesthouse, and one pub, as well as an eight-mile walking loop and sightings of rare migratory birds like the hobby falcon, which two mainlanders with very large scopes spotted earlier today. It’s a wildly popular tourist destination when summer kicks in. Last year there were 16,000 visitors. Today there are four.

During the crossing, I ponder whether Miller spends more time exploring the planet’s outer reaches or his darkest inner realms. Some of the sea stacks and climbing routes he’s named—Altars of Madness, Testament to the Insane, Chaos, the Unforgiven—indicate a relentless mental churning (and a serious heavy metal habit). “The only thing I genuinely fear is regret,” he told me earlier in the week. “Regret is something you can’t go back on. My only regret in life is not seeing Nirvana and Mudhoney on their European tour in 1989.”

Miller has also written an unpublished book, The Realms of Chaos: A Climber’s Guide to Midlife Crisis. I haven’t read it, but I’m gathering it’s tangentially related to the 2004 death of his climbing partner, 59-year-old Les Gorman. The two had just completed the climb of their lives, Testament to the Insane, a 1,600-foot ascent on John’s Head, a Scottish sea cliff that took 26 hours. The day after, on an easy 45-foot rappel, Gorman failed to properly clip in. He “splattered” at Miller’s feet and died. “His legs were totally smashed,” Miller says. “Twenty minutes before he abseiled off that stack, he told me, ‘Nothing happens to you. Everything happens for you.’ ”

“What happened for you in this situation?” I ask.

“I am now absolutely fanatical about people not getting injured,” Miller says.

After we settle into our guesthouse, a five-minute walk from the ferry, Miller takes me on a tour of Tory to scout its six sea stacks and sea cliffs that end in a formation known as the Anvil, a serrated quartz wall 164 feet high that juts 1,300 feet into the sea. It gives me vertigo just looking at it.

“There are at least a couple of lifetimes’ worth of routes on Tory,” says Miller as he scouts an iconic line on a sea stack he calls the Giant’s Head. I ask him if he thinks the island could become an enclave for young entrepreneurial adventurers.

“Rock climbing alone can’t save the island, but surfing, sea kayaking…” His sentence trails off. “The only thing is, to start a business here, you would have to speak Gaelic.”

You would likely also have to get approval from the King. Patsy Dan Rodgers, the 73-year-old King of Tory, has held the throne, which sits in his house, since 1994. He has no official power, but King Patsy Dan is an accomplished primativist artist who’s passionate about his island, and he tries to greet most of its visitors as a sort of ambassador to the outside world.

Our meet-up happens by coincidence after midnight at Club Soisíalta. On the black walk up to the pub, which sits on a hill on the far western edge of town, a fantastical emerald aurora borealis dances across the sky, as if to herald the King’s arrival.

Only three people occupy the bar, but it feels lively, with a banner proclaiming Toraigh Go Braith (Tory Forever) across one end and Meghan Trainor’s “All About That Bass” thumping on the loudspeaker. As we nurse our Heinekens, a dapper gentleman in a derby cap and a leather bomber jacket, with three gold rings in his right ear, quietly slides onto the couch. He’s drinking a long, tall glass of what looks like watered-down whiskey, but I deduce by the sweet smell that it’s Red Bull.

“I love my Red Bull!” King Patsy Dan exclaims. “I was a little heavy on the whiskey, and now I drink between nine or ten of these some days.”

I ask the King what he thinks about rock climbers. “Tory has been praised by rock climbers!” he says.

Miller, who has been silent throughout our conversation, finally speaks up, telling the King that it was he who did the first ascent of the sea stack featured in the photo on the other side of the bar.

“My goodness now!” exclaims the King. “Well I am so very proud of that. But it would give me the creeps to see anybody climbing these cliffs. They are very dangerous!”

Miller politely nods, but his mind is already a million miles away, dreaming up a plan to free-solo the cliff in the King’s backyard tomorrow.

Contributing editor Stephanie Pearson (@stephanieapears) has written about Sweden, India, Colombia, the Falkland Islands, and Brazil, among other places.