San Juan Skyway Scenic Byway, Colorado
The San Juan Skyway links four mountain ranges and five historic mining towns in one 233-mile loop. Between Durango and Telluride, you’ll hit hot springs, ghost towns, and some of Colorado’s most hair-raising mountain passes – including the famous Million Dollar Highway stretch.
Your car will pass through a 15-degree temperature change
As you drive the San Juan Skyway, you’ll climb and drop more than 5,000 feet in elevation between valleys (6,200 feet) and mountain passes (11,018 feet). This creates big temperature swings—about 15 degrees Fahrenheit—in just an hour’s drive.
These quick climate shifts create five different ecological zones, each with its own plants and animals. You can check current conditions on roadside digital displays at Lizard Head Pass, Red Mountain Pass, and Coal Bank Pass, which update every 15 minutes.
Four mountain passes higher than any eastern US mountain await you
As you drive the 236-mile loop, you’ll cross Red Mountain Pass (11,018 feet), Molas Pass (10,910 feet), Coal Bank Pass (10,640 feet), and Lizard Head Pass (10,222 feet). Each one is higher than any mountain in the entire eastern United States.
Red Mountain Pass holds the record as the highest paved mountain pass kept open year-round in North America. To keep it clear, road crews use eight special snowplows modified to work at extreme altitudes.
You’ll navigate a total of 67 switchbacks over 72 miles of steep terrain as you cross these high mountain passes.
You’ll drive without any guardrails on the Million Dollar Highway
Between Ouray and Silverton, you’ll find yourself on a 25-mile stretch with sheer cliffs dropping over 1,000 feet and no safety barriers at all. The road gets super steep with an 8% grade and lots of tight turns cut right into the mountainside.
Some parts are just 22 feet wide, barely enough for two cars to pass each other. If you’re heading south, your car will be on the outside edge with nothing between you and the drop below. Each year, about 2-3 vehicles slide off during winter when conditions get icy.
Snow sheds protect you from massive avalanches every day
When you drive through the Riverside Slide area between Ouray and Silverton, you’ll pass under a 180-foot concrete tunnel built in 1965 after several people died. This structure keeps you safe from up to 30 avalanches each year, some dumping over 10,000 tons of snow.
Nearby, you’ll see a monument honoring 16 snowplow drivers who lost their lives clearing this route since 1935. The Colorado Department of Transportation also maintains seven spots along the way where they use actual howitzer cannons to trigger controlled slides.
They used to charge tolls based on how many wheels your vehicle had
When the road first opened in the 1880s, you’d pay based on the number of wheels on your vehicle. Riding a horse cost 10 cents, a one-horse buggy was 25 cents, and freight wagons paid 50 cents per wheel. Stagecoaches had to pay the highest rate at $2.50.
Otto Mears had 11 toll collectors working in shifts at gates placed at strategic points. The toll system stayed in place until 1921 when Colorado bought the route for $76,500.
You can still see the original toll houses from Crystal Creek and Bear Creek at the Ouray County Historical Museum, along with the accounting books listing every transaction.
You can visit the world’s first commercial AC power plant
Near Telluride, you’ll find the Ames Hydroelectric Plant that made history on June 19, 1891, as the first commercial AC power facility ever built. Westinghouse constructed it using Nikola Tesla’s patents and sent electricity 2.6 miles uphill to the Gold King Mine at 3,000 volts.
When they first turned it on, engineers kept it running for 30 straight days because they were afraid they couldn’t restart it if they shut it down. This setup came four years before the famous Niagara Falls power station and still works today under Xcel Energy with equipment from 1904.
Historic beehive kilns from the mining days still stand in Rico
When you pass through Rico, you can stop to see six cone-shaped stone structures standing 25 feet tall that were built in the 1880s.
These beehive kilns got super hot—around 2,000°F—and turned pine trees into charcoal for silver smelting. Each one needed 35 cords of wood to make 1,500 bushels of charcoal.
In 2018, the Rico Historical Society fixed up three of them, making them the best-preserved mining-era kilns you’ll find in Colorado.
From May through September, you can take tours by walking a short trail from the roadside parking area.
You’re actually driving on millions of dollars worth of gold
The road beneath your tires on the Million Dollar Highway contains an estimated $22 million in trace gold and silver at today’s prices.
When they built the road in the 1920s, construction crews used about 900,000 cubic yards of waste material from the nearby Sunnyside Mine.
In 2003, engineers took core samples and found that some sections contain up to 0.03 ounces of gold per ton of roadbed. After it rains, you can actually see the road surface glitter in the sunlight from all the tiny mineral flecks.
The original toll road from 1883 was completely rebuilt using this valuable material.
A Russian immigrant built the scariest parts of the road
Otto Mears, who people called the “Pathfinder of the San Juans,” designed the Million Dollar Highway back in 1883. He was born in Russia in 1840 and built this challenging route using just basic tools and dynamite.
When it first opened, he charged $5 per wagon (about $150 in today’s money).
Between 1870 and 1892, Mears constructed 450 miles of toll roads throughout the San Juans and personally oversaw the most dangerous section through Uncompahgre Gorge.
You can still see parts of his work today, including 8 tunnels and 23 bridges with stone supports visible at Bear Creek Falls crossing.
An old toll bridge site takes you over a dramatic waterfall
When you drive just south of Ouray, you’ll cross over Bear Creek Falls on a bridge built where the original 1883 toll booth once stood. This strategic spot collected $87,000 in fees during its first year (that’s about $2.6 million today). The wooden bridge you see now replaced the original structure in 1934.
At the pullout, you’ll notice a stone marker showing where travelers once paid between $1-$5 depending on their vehicle. Below you, Bear Creek Falls drops 227 feet through a narrow granite canyon, and you can step onto a viewing platform that hangs right over the gorge.
Volcanic activity created Red Mountain’s bright red color
When you spot the bright crimson peak from the highway, you’re looking at a collapsed volcanic cone filled with iron-rich minerals that oxidized over millions of years.
During eruptions about 35 million years ago, the mountain’s core heated up to more than 1,200°F.
Between 1860 and 1920, miners pulled out $850 million worth of gold, silver, and other minerals from three major mines in just 4 square miles.
The Red Mountain Mining District produced over 30 million ounces of silver, and geologists have identified 13 rare minerals here that don’t exist anywhere else in North America.
Ghost towns from the mining era sit just minutes from the main road
Within 5 miles of the byway, you can explore 12 abandoned mining towns. Animas Forks has 8 intact buildings, while Alta Ghost Town near Telluride features an 1891 powerhouse that’s still standing. At 11,600 feet elevation, Carson Ghost Town has five cabins you can visit.
Just 8 miles south of Ouray, Ironton Ghost Town includes 16 structures with the original post office still intact.
Most of these sites are managed by the Bureau of Land Management as Abandoned Historical Sites, so you can visit them via unpaved roads, but you can’t take any artifacts home with you.
High elevation affects both you and your car in unexpected ways
When you reach the highest points on the San Juan Skyway, the air pressure drops to just 68% of sea level. This means your car’s engine loses about 35% of its power because there’s less oxygen.
Your body also gets 25% less oxygen with each breath, which can cause altitude sickness within half an hour.
You might notice your reactions slowing down and your judgment getting worse above 10,000 feet. Modern cars will even warn you about decreased braking power above 9,000 feet.
If you’re traveling during summer, you should use special radiator coolant designed for high elevations.
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