When southern Spain trembles in heat, when dogs seem to be panting their last breaths in narrow bands of shade in the white villages of Andalusia, northern Spain keeps cool.

Its heart is Asturias, the old kingdom that makes Spanish hearts swell. This was the only part of the country never conquered by the Moors; even the Romans struggled to get much of a foothold. In Asturias, Spain becomes a dappled place of woods and tilting pastures, moderate temperatures and soothing winds, tumbling clouds, and deep valleys pitched between spectacular peaks.

Oviedo, the capital, is where Javier Bardem’s character invites his love interests, played by Scarlett Johansson and Penélope Cruz, to join him for a weekend in Woody Allen’s film Vicky Cristina Barcelona.

There is something of the film set about the town, those tall 19th-century windows enclosing balconies, the squares flanked by churches and palaces of golden sandstone, the shop interiors that resemble backdrops from a costume drama. But I had not come only for Oviedo; I was heading to the mountains and the sea that surround it.

The Deva River winds through the town of Potes.

I picked up a rental car and followed the coast eastward before turning into the Picos de Europa—the Peaks of Europe. These mountains, all limestone cliffs and colossal massifs, were named by sailors. They are said to have been the first signpost of home for ships returning to Europe from the New World.

The road into the Picos is as dramatic as the peaks themselves, twisting through the narrow Hermida Gorge, where both road and sky are pressed between towering walls of rock. At the far end of the gorge, travelers emerge in the storybook valley of Liébana and the medieval town of Potes.

Beyond the town, among meadows, is the monastery of Santo Toribio de Liébana. It was here that Beatus, an eighth-century monk, wrote his Commentary on the Apocalypse. A museum in Potes exhibits the illuminated versions, the colorful pages dancing with angels and demons.

Hotel del Oso, a mountain inn, is attended by waitresses in traditional Asturian dress. Its two shambling Saint Bernard dogs resembled somnolent members of a gentlemen’s club, snoozing away the afternoons on the veranda overlooking the pool. In the evenings, the women brought us bowls of delicious fabada-bean stews and glasses of cider. At night, it’s tempting to lie awake listening to the soft chorus of cowbells through the open window, drifting down from the dark pastures above the hotel.

Commentary on the Apocalypse, an eighth-century illuminated manuscript, is displayed at a museum in Potes.

The next day, along with my guide, Alex Asensio, I set off from Llanes over the Sierra de Cuera, a coastal mountain range on a road curving upward through woods of chestnut and walnut trees.

From the top of the pass, we looked over plunging valleys where pastures dotted with cows rose to bare limestone peaks. Nestled into the folds of the valleys were small houses used by families who brought their livestock to these summer pastures. These were some of the last shepherds in Europe, moving with their herds like the nomads of Central Asia in a tradition that here dates back 3,000 years.

For Asensio, these mountains are a playground. He leads treks through their gorges, climbing trips up their most spectacular peaks, and caving pursuits and canyoning adventures in their fast-river canyons. But they are also part of his heritage. These mountains are home to the remaining native speakers—barely 100,000—of his grandparents’ Asturian language.

Near the village of Sirviella, we called in on Pepin, a traditional farmer who breeds Asturian ponies and the local Xalda sheep. They were first recorded by the Greek historian Estruban, who admired the black tunics made from their wool in the first century B.C.E.

At Hotel del Oso, the mountains are enjoyed in full splendor.

Sitting by his wood pile outside a barn of weathered boards, he told us about the cider that has been central to Asturian culture since the time of the Romans. “Anyone can make cider,” said Pepin with a shrug. “But in Asturias, it is the culture that surrounds it that is important.” He opened a bottle and poured it at arm’s length, so a long stream frothed into the glass. “It is drunk like this,” Pepin continued, “only a mouthful at a time, poured to produce a froth. The glass is then handed round the company, one by one. Cider drinking should be social, a way of sharing, a statement about community.”

The next day, we walked a coastal stretch through hedgerows of blackberries, brambles, and ferns to Santiago de Compostela. Millennia ago, Asturias was settled by the Celts, and I realized that this coastline felt similar to the coast of my Irish childhood. Unlike Spain’s Mediterranean costas, with their rows of beach umbrellas and docile seas, this was an Atlantic affair of tides, rock pools, and sandy strands between headlands of gorse and purple-flowering heather.

In the evening, I drank Asturias’s cider in a raucous bar where a local band was reeling through traditional Asturian music. Ethnographers may argue about Asturias’s Celtic heritage, but anyone who has heard this whining gaita, a small bagpipe, and the pitu montañés, a flute akin to the recorder and the tin whistle, will have no doubt about the connection. Close your eyes and listen—you could be in a pub in Connemara.

Trips to Asturias can be arranged through Pura Aventura, a company that organizes outdoor-adventure travel in Spain. This itinerary was part of its Northern Spain Signature Drive, which begins at $2,500 and includes accommodations, private tours, rental cars, and certain meals

Stanley Stewart, a journalist based in Dorset, U.K., and Rome, is a contributing editor at Condé Nast Traveler and a regular contributor to The Sunday Times of London. He is a fellow of the Royal Society of Literature, and his most recent book is In the Empire of Genghis Khan