A Guide to Boulder’s Flatirons

The Flatirons are the striking, slanted, reddish-brown sandstone formations that make up a portion of Boulder’s foothills on the west side of town. They are Boulder’s most iconic landmark, and you’ll see their likeness in business logos and artwork throughout town.

By: Visit Boulder
Updated: March 25, 2024

Whether frosted with snow, cloaked in fog, or glowing warm and red under sunny skies, the Flatirons offer the quintessential Boulder view. Once you snap a few shots of them from afar, head toward the foothills to explore them up close. You can help protect their natural beauty by remembering these Leave No Trace Principles.

3 Ways to Explore the Flatirons

The Flatirons belong to the more than 45,000 acres of Boulder’s protected Open Space & Mountain Parks, giving both locals and visitors extensive recreational access to these rocky towers (as well as providing habitat for wildlife ranging from squirrels and rabbits to bats and falcons to bears and even mountain lions). Here are our three favorite ways to explore them:

1. On Foot

Plenty of trails will take you around and up to the Flatirons, and many of them start from the Chautauqua Trailhead, off Baseline Road. Please allow adequate time for parking, as this can be very a busy area.

For an easy-to-moderate hike, take the 2-mile Flatirons Loop Trail, winding through the forest beneath the Flatirons. Or up the ante by continuing along the strenuous, 3-mile Royal Arch Trail, which ends at a natural rock arch with awe-inspiring views of Boulder and its surroundings.

Another option is the hike to Woods Quarry, where you’ll get a view into the site of a historical sandstone quarry, plus enjoy a spectacular view from the stone benches that were assembled by some industrious visitors. These trails travel through ponderosa pine forest, over rocky scree fields, and across open fields, offering various views of the Flatirons and Boulder along the way.   

2. On the Ropes

The best way to get up close and personal with the Flatirons? Climb them! The First and Third Flatirons offer some of the most popular multi-pitch rock climbing routes in the area (and country!). The trail to the First Flatiron climbing access can be challenging, but you’ll be rewarded with long, varied climbs that range from about four to 10 pitches.

The popular Third Flatiron, which offers even more routes, is usually closed to climbers and hikers from early February to late July to protect nesting raptors. Over the years, climbers have scaled the Third Flatiron while wearing roller skates, under the full moon without headlamps, and even while completely naked! But maybe save that for your next trip.

3. On the Lawn

Not feeling up to a hike or climb? You can still get your fill of the Flatirons — while filling your belly. Pack a picnic (we recommend buying your provisions at the Boulder Farmers Market on Wednesday evening or Saturday morning) and spread out a blanket on the grassy lawn at Chautauqua Park. This is the perfect spot to enjoy a meal beside the Flatirons while watching the parade of people (and their pooches) heading up the hill for a hike. Afterward, you can hit the tennis courts, take the kids for a spin around the playground or catch a show at Chautauqua Auditorium

Park-to-Park Free Shuttle

Headed to the Chautauqua area on a summer weekend to hike among the Flatirons? Ride the free weekend shuttle to get there stress-free and avoid parking fees. Here's all the information on the Park-to-Park hiker shuttle, which runs weekends Memorial Day to Labor Day. 

A Bit of History

These geologic formations are nearly 300 million years old. Although we know them today as “the Flatirons,” in the early 1900s they were called the “Chautauqua Slabs” or “The Crags.” When pioneer women said they thought the rocks looked like flat, metal irons used to iron their clothes, the name “Flatirons” stuck.

There are five numbered Flatirons, which run north to south along the eastern slope of Green Mountain in Southwest Boulder. These are what people usually mean when they refer collectively to “The Flatirons,” though you can also include numerous other named formations, such as the Seal, Devil’s Thumb, the Flying Flatiron and the Matron.

Insider Tips

Sharp eyes will see the huge letters “CU” (for the University of Colorado) near the top of the Third Flatirons. These were painted on the rock by two CU freshmen in 1949.

When the sun warms the area’s ponderosa pines, their bark can give off aromas resembling ice cream and chocolate.

On most OSMP trails in this area, dogs must be on a hand-held leash at all times unless they meet the voice and sight control standard and display a City of Boulder Voice and Sight tag.

Winter is the perfect time to hike the Flatirons. you won't need snowshoes, just hiking boots and possibly snow cleats (such as Yak Trax) for traction.

Want More? 

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