The Devil’s Slide, Utah
Two gray walls of rock run straight up a Utah mountain, looking like someone carved a giant water slide into the cliff. The Devil’s Slide isn’t the work of devils or humans. It’s pure geology, with a story that goes back to ancient seas. Here’s why this natural wonder stops traffic on I-84.
A Slide Fit Only for the Devil
Devil’s Slide got its name because it looks like a massive playground slide built for Satan himself. Two tough limestone walls stand about 40 feet tall, with a worn-out chute between them that’s roughly 25 feet across.
The rock walls have this polished smoothness from centuries of wind and rain that almost looks deliberate.
Pull off at milepost 111 on I-84 where there’s parking spots on both sides of the highway. The Weber River runs between you and the slide, adding that perfect touch to your photos.
When It Was Called “Gutter Defile”
Back in the 1860s, mapmakers used “defile” for any narrow gap in mountains.
Before it got its hellish name, early railroad guys like John Walker just called this weird formation “Gutter Defile” on their maps. Makes sense – it looks like a giant rain gutter slashed into the mountain.
The Union Pacific crews in 1868-1869 used this spot as a landmark while they busted their backs laying track through the canyon.
The Guy Who Named It
We can thank a railroad worker named James John Walker for the name “Devil’s Slide.”
His family was among the first to set up in nearby Croydon, and family stories say he was working on the tracks around 1868 when his buddies asked what to call this weird rock chute. His answer stuck.
Walker was sweating it out with the crews finishing the final stretch of the Transcontinental Railroad, completed in 1869. His family kept this story alive in their papers, now sitting in Utah’s state archives.
What the Natives Called It
There’s this great nugget from an 1888 Salt Lake Tribune piece where a Native American guide called the rock formation “Devil’s War Club” instead. Different eyes, different vision of the same rocks.
This story ran on June 28, 1888, written by reporter named Allan Forman. The guide was probably from the local Shoshone tribe who knew these mountains better than anyone.
Pretty rare for newspapers back then to even mention Native American takes on landmarks, making this an unusual historical footnote.
First Press Coverage
The name “Devil’s Slide” first hit print in an 1875 newspaper article by Carl Ege from the Utah Geological Survey.
So yeah, the name’s pushing 150 years old now. That article got folks curious about this rock formation and brought the first wave of tourists out to see it. The story ran in a Salt Lake City paper and put the spot on early Utah tourist maps.
Not long after, Union Pacific started listing it as a “point of interest” for passengers chugging through Weber Canyon.
Rock Hardness Matters
Devil’s Slide is a perfect lesson in how different rocks get beat up by weather at different speeds.
The outer walls are tough limestone that can take a punch, while the middle channel is “shaly limestone.” If you’re into the details, those outer walls score about 3-4 on the Mohs hardness scale, while the inner layer is a softer 2-3.
You’ll spot similar patterns elsewhere in the Wasatch Range, but none this perfect. Even the colors tell the story – the harder sides are gray, the softer middle more tan or light brown.
Born Under the Sea
The limestone that makes up Devil’s Slide was laid down about 170-180 million years ago at the bottom of a shallow sea that once covered Utah, Montana, Wyoming, and parts of Arizona.
This was middle Jurassic time, when most of western North America was underwater. Picture a warm, life-filled sea, loaded with shell creatures whose dead bodies piled up to form this limestone.
Wild fact: these rock layers formed roughly 10 million years before famous dinos like Stegosaurus and Allosaurus were even a thing.
Part of Something Bigger
The rocks making up Devil’s Slide belong to what geologists call the Twin Creek Limestone. Across northern Utah, this rock layer is a monster, roughly 2,700 feet thick. Experts split this formation into seven different layers, each with its own quirks.
Devil’s Slide sits in what they call the Leeds Creek member. Rock experts date these layers by the fossil shells stuck in them, which match other Jurassic beds across the western states.
It’s just one small visible piece of a massive layer cake that runs under much of northern Utah.
Flipped on Its Side
About 75 million years ago, some serious earth forces during mountain building flipped these once-flat sea-bottom rocks to stand almost straight up.
This massive land crunch, called the Sevier Orogeny by geologists, pushed rock layers east as the earth folded like a rug getting shoved against a wall.
The rock tilt at Devil’s Slide is almost exactly 90 degrees from how it started out flat. Look close and you’ll see where some rock layers cracked during this violent flip, with small fault lines cutting across the formation.
Long Way Down
The twin rock walls of Devil’s Slide stretch several hundred feet down the mountain slope, making for an amazing sight from the highway. To be exact, they run about 375 feet from top to bottom.
The walls aren’t ruler-straight but curve slightly as they follow the old sea-floor shape. Pro tip: the north parking area gives you the best view of the whole thing, where you can see the full scale of these rock walls against the mountain backdrop.
Devil Takes a Bath
Local folklore says the Devil slides down this rock chute every morning to take a bath in the Weber River below. A bit of spookiness that adds flavor to the place. This tale goes back at least to the early 1900s among the railroad crews.
The Weber River at the slide’s base has some decent trout fishing spots, by the way. Old-timers from the mining camps used to claim that on hot summer days, steam would rise from the middle channel – supposedly the Devil’s breath warming the rocks.
Not the Only Devil in Town
Utah’s Devil’s Slide isn’t one of a kind – there are four other rock formations in America with the same name, including ones in California and Montana (just north of Yellowstone).
California’s Devil’s Slide perches on a coastal cliff, while Montana’s version clings to a mountain slope like Utah’s.
But the Utah formation has the most clear-cut “slide” path between its rock walls, making it the poster child for this type of geology.
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