Idaho has two waterfalls that were never dammed, and a 29-mile drive takes you right to them

They’ve never been dammed or diverted

You can drive most of Idaho and never find a major waterfall that hasn’t been rerouted for irrigation or strapped to a hydroelectric plant.

But 29 miles northeast of a tiny potato-farming town, two big falls still pound over volcanic rock the same way they have for thousands of years.

The Mesa Falls Scenic Byway through the Caribou-Targhee National Forest takes about an hour without stops, but the canyon views and the falls themselves can fill half a day.

The road is paved and easy the whole way, and what you find at the end of it is worth every mile.

A volcanic eruption built this whole landscape

The byway earned its Forest Service Scenic Byway title in 1989, one of more than 30 scenic byways across Idaho.

The land it crosses was shaped by the Yellowstone hotspot, the same system that fuels the geysers you hear about in the national park.

About 1.3 million years ago, a massive eruption created the Henry’s Fork Caldera and spread at least 280 cubic kilometers of ash across Wyoming and most of Colorado, Nebraska and Kansas.

The rock the waterfalls pour over, called Mesa Falls Tuff, formed during that eruption. Today, forests, open meadows and river canyons cover what was once a volcanic wasteland.

Ashton grows the seed potatoes that feed the country

The byway starts in Ashton, a farming town of about 1,000 people sitting at 5,259 feet above sea level.

Fremont County around Ashton is Idaho’s largest certified seed potato growing region, and locals call the town the seed potato capital of the world.

Cold winters and volcanic soil keep the crop disease-free, and those seed potatoes ship to farms across the country.

As you head northeast out of town on Highway 47, rolling fields of potatoes, barley and wheat spread out on both sides, and the Grand Teton range rises along the horizon.

Warm River has otters and eagles by the bridge

About nine miles from Ashton, you pass through Warm River, one of the least populated cities in the state. The community sits along the Warm River, which flows into the Henrys Fork of the Snake River just nearby.

Pull over near the bridge and look down. River otters slide through the current, trout hold in the shallows, and bald eagles circle above the tree line.

If you want to stay awhile, the Warm River Campground sits right next to the water with sites for both tents and trailers.

Lower Mesa Falls draws fewer crowds for a reason

Fourteen miles from Ashton, the road brings you to Lower Mesa Falls.

The Henrys Fork drops 65 feet over a basalt cliff here, and you can see the whole thing from the Grandview Overlook about a quarter mile away.

For a closer look, the Mesa Falls Nature Trail runs about a mile one way from the Upper Mesa Falls area down to an overlook above the Lower Falls.

Most people skip this one and head straight to the upper falls, so you get a quieter spot and more room to take it in.

Upper Mesa Falls throws mist 114 feet into the canyon

Upper Mesa Falls is the main draw, and you’ll understand why the moment you reach the rim. The water drops 114 feet in a broad sheet roughly 200 feet wide over ancient volcanic tuff on the Henrys Fork.

A paved boardwalk with stairs and viewing platforms leads you right to the brink, and several of those pathways work for visitors with mobility challenges.

On summer mornings, sunlight passes through the mist and throws a rainbow across the canyon. You feel the spray on your face before you even reach the closest platform.

The Big Falls Inn started as a 1915 hotel and dance hall

Right near the upper falls, the Mesa Falls Visitor Center sits inside the Big Falls Inn.

The Snake River Electric Light and Power Company built the place around 1915, and in those early years it ran as a hotel, cafe and dance hall.

Ranchers and travelers on the Yellowstone Highway used it as a waystation for decades. The Forest Service took over in 1986 and worked with Harriman State Park and other groups to restore it.

The inn now holds a spot on the National Register of Historic Places, and inside you can walk through exhibits on the area’s natural and cultural history during the warmer months.

The falls exist because softer rock wore away first

Every waterfall needs hard rock over soft rock, and that is exactly what the Yellowstone hotspot left behind here. The 1.3-million-year-old eruption fused superheated ash into a thick, erosion-resistant layer of tuff.

Softer rock around it wore down over hundreds of thousands of years.

Then, between 200,000 and 600,000 years ago, the Henrys Fork carved a wide canyon that basalt lava flows partly filled.

The river cut its current channel through that basalt, forming the inner canyon and the dramatic drops you see at both waterfalls today.

The Henrys Fork starts at 52 degrees and never warms up

The Henrys Fork of the Snake River is one of the most famous fly-fishing rivers in the country, and fly anglers come from all over for the large wild rainbow and brown trout.

The river begins at Big Springs near Island Park, where over 120 million gallons of water push from the ground every day at a constant 52 degrees Fahrenheit.

Beyond the fishing, bald eagles, ospreys and moose live along the corridor.

The river moves through gentle ranch land, timber-covered canyons and spring-creek stretches with some of the most varied scenery in eastern Idaho.

Harriman State Park sits inside an 11,700-acre wildlife refuge

Near the northern end of the byway, you meet U.S. Highway 20 close to Harriman State Park. The park sits within an 11,700-acre wildlife refuge in the Greater Yellowstone Ecosystem.

The Harriman and Guggenheim families, connected to Union Pacific Railroad wealth, ran this land as a private cattle ranch starting in 1902.

The Harriman family donated the property to Idaho in 1977 on the condition that it stay a state park and wildlife refuge. More than 20 miles of trails cut through meadows, forests and along the Henrys Fork.

Moose, elk, sandhill cranes and trumpeter swans are common here, and this is one of the best spots in Idaho to see the swans up close.

Johnny Sack built every chair and lamp by hand

A few miles east of Mack’s Inn off Highway 20, Big Springs ranks among the 40 largest springs in the country and holds National Natural Landmark status.

You can watch large rainbow trout from a viewing bridge over the water, though fishing is off-limits in the immediate area to protect them.

Nearby sits the Johnny Sack Cabin, a handcrafted log home a German immigrant named Johnny Sack built between 1932 and 1934.

He cut and shaped every piece of furniture using local wood and stone, and a split-bark design still marks the trim, ceiling lamps, chairs and desks.

The cabin joined the National Register of Historic Places in 1979 and opens to visitors each summer.

Winter shuts the road and opens it to snowmobiles

The byway runs from roughly mid-May through the first heavy snowfall in the fall, depending on conditions.

Once winter hits, Forest Service Route 294 closes to cars and becomes a groomed snowmobile and cross-country skiing route. A day-use fee applies at the Mesa Falls area during the driving season.

At Ashton, the byway connects with the Teton Scenic Byway if you want to extend your road trip toward the Teton Range.

From the northern end at U.S. Highway 20, Yellowstone National Park is less than an hour’s drive east, so you can stack both trips into the same week without much backtracking.

Drive the Mesa Falls Scenic Byway in Idaho

You can pick up the Mesa Falls Scenic Byway in Ashton, Idaho, at the junction of U.S. 20 and Idaho Highway 47.

The route runs about 29 miles northwest to U.S. Highway 20 near Harriman State Park, and the drive takes roughly an hour without stops.

Upper and Lower Mesa Falls sit about 14 to 16 miles northeast of Ashton along the way. The Mesa Falls Visitor Center at the Big Falls Inn opens on a seasonal schedule that depends on snow and road access.

Check the Caribou-Targhee National Forest’s official website for current conditions, fees and closure dates before you go.

This article was created with AI assistance and human editing.

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