Pets allowed
Elevation Gain
1,200.00 ft (365.76 m)
Trail type
3.20 mi (5.15 km)
Please respect the outdoors by practicing Leave No Trace. Learn more about how to apply the principles of Leave No Trace on your next outdoor adventure here.

This is a very scenic, moderately difficult hike up the gentle slopes of Green Mountain outside of Boulder. The highlight is a natural rock arch spanning about 20 feet of air, which the trail passes right beneath. The view from here is great as well, stretching all the way to Denver's skyline and across the Great Plains.

Multiple routes in the mountain park link up with the Royal Arch Trail, but the most direct access via Bluebell Road, from either Chautauqua main parking or Enchanted Mesa parking. Walk up to Bluebell Shelter and begin the trail from there.

The hike begins as a gradual incline through shady Bluebell Canyon. Soon you will start to switchback up a piney ridge and gain a vantage of Boulder and the surrounding landscape, including the Flatirons. You will drop down again for a short distance, then back up, starting a somewhat steep, final climb. Soon after the start of this steep section you will pass Tangen Spring, which trickles with water most of the year. There is a small cave here that kids (or adults) can crawl into and explore. For the more intrepid spelunkers, climbing up and out the back of the cave affords a great view of the arch that not many people get to see.

Royal Arch is an eroded outcrop of the Fountain Formation, the hardened sandstone layer that is exposed all along this part of the Rocky Mountain front. It is the same type of rock that makes the nearby Flatirons. Once you reach this spot, take time to relax in the shade, rehydrate, take in the views, and enjoy your reward for finishing the hike.

Note: This is a Voice and Sight Trail, which means that dogs are permitted off leash with the following conditions: (1) Guardians must be registered in the Voice and Sight Tag Program, (2) Voice and Sight Tags must be displayed on the dogs, (3) Guardian has a leash for each dog, with no more than two dogs.

Logistics + Planning

Preferable season(s)




Parking Pass

Not Required


Unique geological feature. Expansive views over Boulder/Great Plains.


Extremely crowded. Limited parking.

Trailhead Elevation

5,710.00 ft (1,740.41 m)


Rock climbing
Big vistas


Nearby Lodging + Camping


Absolutely fantastic view at the top! But it is a moderately hard hike. It is mostly uphill the whole way there and there are a lot of rocks to step on. Not being from Colorado makes it a little harder with the altitude difference. We did not find the cave to crawl through but the archway was really cool and the view when you walk through is amazing.
The loop seen on the trail guide is called the Flatiron Loop Trail. I (and a friend) hiked the loop in late May of this year (2016). From the trail one can see expansive views of the Great Plains, the city of Boulder, and even the city of Denver at a far and hazy distance. There were not, however, panoramic views of the high peaks from this loop trail. As for the trail itself, expect some rocky portions and some gravelly uphill portions. A little before the split to Royal Arch is reached, the loop trail runs steadily downhill with plenty of rocks for better footing. Pass the Royal Arch split and continue downhill to follow the loop. The trail had minimal stairs and a small river crossing or two. We did see a small herd of mule deer cross the trail as well. The trail is initially sunny and later shaded, then becomes sunny again. If you take Bluebell Road back down instead of the trail shown on the map on this site, take note of a short but steep spur up the hillside that affords great views of the foothills once at the top. Enjoy!
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