The Flatiron’s are well-known and highly-visible as the striking sandstone formations that run along the eastern slope of Green Mountain outside of Boulder on the Colorado Front Range. As one of the city’s most iconic landmarks, the Flatirons provide great access to outdoor recreation.

According to the City of Boulder, the Flatirons are part of the Fountain Formation, a rock unit deposited about 280 million years ago. About 65 million years ago the Rocky Mountains formed as a result of tectonic collision, and the rocks formed by the Fountain Formation rose up and tilted, becoming the Flatirons seen today.

Hiking is a great way to explore the Flatirons, and there are plenty of trails that will lead you through them. According to Visit Boulder, many hiking trails begin from the Chautauqua Trailhead off Baseline Road. Before hitting the trails stop by the Ranger Cottage for restrooms, maps, brochures, hiking suggestions, and information about weather, trail conditions, and wildlife closures.

The Flatiron Loop Trail is a two-mile, easy-to-moderate hike that winds through the forest beneath the Flatirons. Another option is the hike to Woods Quarry, which leads to the site of a historic sandstone quarry. According to the City of Boulder, the quarry provided sandstone for Boulder’s buildings and sidewalks in the 1890s. Visit Boulder says both of these trails “travel through ponderosa pine forest, over rocky scree fields, and across open fields, offering various views of the Flatirons and Boulder.”

Royal Arch Trail is another popular but more challenging hike in the Flatiron area. It travels about three miles round-trip, and features a natural rock arch at the turnaround for the out-and-back route, along with picturesque views of Boulder and its surroundings.

The Boulder Flatirons stand as a reminder of Colorado’s natural beauty, and provide some amazing hiking and scenic views.

Read more about how the Boulder Flatirons were formed here.

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