The Boulder Flatirons, one of Colorado’s most photographed natural attractions, are an iconic facet of the Front Range. Consisting of five large flatirons, a type of rock formation created by differential erosion of a harder layer of rock on top of a softer layer, some geologists estimate that these popped up between 35 and 80 million years ago.

RELATED: 40 Must-See Colorado Destinations!

The Flatirons in Boulder, Colorado
The Flatirons in Boulder, Colorado. Photo Credit: beklaus (iStock)

The Boulder Flatiron area is a very popular Front Range destination for climbers and hikers, with rock climbing route grades ranging from an easy 5.0 to a very difficult 5.14.

LIKE COOL ROCKS, EH?: You’ve never seen rocks like this.

Once upon a time, there was a large 50 foot tall “CU” on the 3rd Flatiron. It was put up during the 1950s but painted over by the city of Boulder in 1980 in an attempt to keep the flatirons looking as natural as possible.

WANT EVEN MORE COOL ROCKS?: You Won’t Believe This Is In Colorado!!

Chautauqua Park Bear Peak OutThere Colorado
Bear Peak justs above the Boulder Flatirons in the distance

The Flatirons haven’t always been called “the Flatirons”: at one point, they were referred to as the “Chautauqua Slabs”, as well as “The Crags” during the early 1900s.

The origin of the “flatiron” name has been lost to time, though many think it comes from the rock’s resemblance to an old clothing iron.

Boulder Flat Irons OutThere Colorado

If you’re looking to explore the Boulder Flatirons for yourself, the easiest route starts at the Chautauqua Park Trailhead.

RELATED: 40 Must-See Colorado Destinations!

Leave a Reply

What We Believe

We are driven by our deep respect for our environment, and our passionate commitment to sustainable tourism and conservation. We believe in the right for everyone - from all backgrounds and cultures - to enjoy our natural world, and we believe that we must all do so responsibly. Learn More