I WENT TO SLEEP LAST NIGHT IN COWBOY COUNTRY, a place of sandy canyon walls and dusty tumbleweed, and woke up this morning amidst mist-shrouded mountains in an age-old temperate rainforest. This magical trip through time and geography is a feature of the American Empress, a stately, paddlewheel steamer that cruises along the mighty Columbia River, bordered on one side by Oregon and the other by Washington State.

We are following the same route as early- 19th-century explorers Meriwether Lewis and William Clark. Their mission: to determine what lay in the unknown lands between the Mississippi River and the Pacific Ocean – and if those lands could be spanned by river routes.

Like them, we are discovering many scenic wonders, particularly when passing through the aweinspiring Columbia Gorge. But whereas they were roughing it on foot and by canoe, we are doing it in considerable style.

American Empress in the mountains

American Empress in the mountains

My en suite balcony room has warm, designer distressed wallpaper and ornately-framed artwork, along with a flat-screen TV, pod coffee maker and iPod dock. We dine in the elegant, chandelier-lit Astoria Dining Room, which is enhanced by views out of the large windows on each side and five course menus featuring such treats as succulent red salmon, fresh from the Pacific Ocean, and excellent wines from both Washington and Oregon.

The top deck’s conservatory style River Grill, which opens on to a patio overlooking the stern, serves casual breakfasts and lunches, all-day coffee and cookies and, in the evening, a short, classic menu – lobster, crab, steak. (Unlike most specialty restaurants on cruise ships, there is no extra charge.) And the Paddlewheel Bar has views through the giant, red paddlewheel, a mesmerising sight when the spray catches the setting sun. There, they serve craft beers – bitters, pale ales and stouts – from local microbreweries and even small batch offerings of bourbon, vodka and other spirits from the region’s small distilleries.

Carrying 224 passengers and exuding Victorian style sumptuousness, the American Empress may look like she’s been around a century or more but, in fact, was only built in 2003. Purchased from a previous owner by the American Queen Steamboat Company – which also operates the larger, better known American Queen on the Mississippi River –it spent £3 million on renovations before launching her on the Columbia River in early 2014. She has since created such a splash that the 2016 season has been extended to run from March to November.

Starting in Spokane, Washington

We began our adventure with an overnight stay in the delightful, early 20th-century Davenport Hotel in the eastern Washington State city of Spokane, joining the boat at the pretty, small riverside town of Richland, where vineyards climb the gentle hills behind cherry orchards. By dinner time, we’re in sunny, warm Oregon, surrounded by canyon walls.

This might be a river cruise but it’s as much about history and the environment as it is about lounging in luxury. Lawrence Cotton, the onboard ‘riverlorian’, who gives daily talks on our surroundings, tells me we are travelling through ‘shrub-steppe’, not far removed from a desert. It’s also part of the Oregon Trail that was travelled by about 400,000 settlers in the mid-1800s as they headed west in search of land, wealth and new lives. The terrain is easily viewed by one of the ondeck rocking chairs that I make my own.

Swiftly, we come to two dams, the McNary and the John Day, where the 110ft-drop lock was the world’s tallest until China’s Three Gorges project. In their background are the rugged mountains of the Pacific Northwest.

Rapids Columbia River

Several dams, here at The Dalles (or rapids), control the flow of the powerful Columbia River

Our first stop is The Dalles (meaning rapids) where Lewis and Clark found their path blocked and took to the river in canoes. Across the river on the Washington side, the bank is ridged with gnarled peaks, their lush, green, grassy covering looking prehistoric, the setting for a sci-fi film.

There, on the Oregon side, the coach that follows the American Empress – itself gaily decorated like a steamboat – takes us on one of the voyage’s free hop-on hop-off tours to the timber and stone Columbia Gorge Discovery Centre. Set on the river’s edge, it has picture windows overlooking dramatic primordial scenery. This area, we learned, was the home of the impressively-tusked Columbian mammoth, which reached 13 feet in height. The gorge itself was created in the last Ice Age when the ice blocking a bottleneck melted, allowing the waters of a lake the size of Montana to rush up to 2,000 feet high into the gap. By the late 1800s, steamboats carrying thousands of Oregon Trail emigrants were plying the route to the coast.

Hood River

Our next Oregon stop is the picturesque town of Hood River, overlooking scores of windsurfers and sailing boats taking advantage of the gorge’s wind-tunnel effect. Mt Hood, the 11,000ft volcanic peak and winter ski resort, looms not too far away. There, our coach takes us to WAAAM, the Western Aircraft and Automobile Museum, a collection of 100 light planes, plus many cars, in several hangars, all run with a mom-and-pop restaurant feel by volunteers of a certain age. Other passengers take the short riverbank stroll to town.

Next day, we’re in the midst of huge pine trees and rock walls at the tiny town of Stevenson, Washington (our guide, Trudy, says it encompasses “1,500 people if you drag them all in from the hills”). A Santa Fe freight train rumbles past for what seems like an hour and then our tour takes us inside Bonneville Dam to view the giant electricity-making generators and – through huge windows – salmon and trout fighting their way up the enormous fish ladder.

Onward from Multnomah Falls to Portland, Oregon

Our drive along the final stretch of the gorge’s sinuous highway, created in the early 20th-century as a tourist attraction, leads to such landmark sites as the circular marble and stone Art Deco Vista House perched on the top of 733ft-high Crown Point – it looks more like an heroic monument than one of America’s earlier roadside rest stops – and, among a string of roadside waterfalls, Multnomah Falls, which crash 611 feet in two tiers to ground level. I climb the steps to the viewing area and then stand on Benson Bridge, which crosses the falls at the bottom of the first tier, to be engulfed by the cascade’s spray and noise.

Back on board the American Empress, we see the Columbia Gorge end as suddenly as it began and we’re in an area of mellow fruitfulness, before heading past Portland, Oregon’s largest city and on to Astoria, the oldest American settlement west of the Rocky Mountains. We dock in its heart, across from the Heritage Museum, continuing by bus to the 600ft Astoria Column, which offers splendid Pacific Ocean coastal views, and, by foot, along the river walk, passing a colony of lounging sea lions. Then, some of us decide to pay a bit extra to continue to Fort Clatsop, where Lewis and Clark spent the winter of 1805-06 following their epic journey half way across the American continent. It’s our last day and, as the sun sinks over the ocean, we head back east to spend the night in cosmopolitan Portland.