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The classic long mountain route in Boulder.

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8,407' 2,562 m


5,427' 1,654 m


5,214' 1,589 m


5,282' 1,610 m



Avg Grade (7°)


Max Grade (29°)

Dogs Leashed

Features Birding · Fall Colors · River/Creek · Views · Wildflowers · Wildlife

Check the City of Boulder site for more information here: here


This route lets you see everything that Boulder has to offer for mountain running by traversing five tall mountains in Boulder: South Boulder Peak, Bear Peak, Green Mountain, Flagstaff Mountain, and Mt. Sanitas.

Need to Know

From November to April, there is usually ice on the higher parts of the route. Microspikes are recommended for these sections. The most significant creek crossing in the first half of the route is at Bear Canyon, after descending from Bear Peak just before you head up Green Mountain. This is the best place to fill up water mid-journey, if you need to. The next (and last) place to get reliable water is the drinking fountain at Eben G. Fine Park.

Runner Notes

This is a long route that has a large variety of terrain and trail that has a lot of gain in a short distance. There are a couple of creeks and one water fountain to get water from. From November to April, there is usually ice on the higher parts of the route. Microspikes are recommended for these sections.


From the South Mesa Trail, head up the wide Mesa Trail as it gradually climbs through open terrain. Turn left onto the Shadow Canyon connector trail after 1.5 miles and head to the mouth of Shadow Canyon. From the mouth of the canyon, it's one mile to the top and 1,600' feet of gain, which makes it one of, if not the steepest climb in Boulder. Shadow Canyon is very rocky and steep until the last few hundred feet, when the canyon opens up a little bit to gentler switchbacks on smooth trail.

At the junction at the top, turn left and for the final 500 feet up South Boulder Peak on steep but smooth trail. Scramble up the talus to the top. From South Boulder Peak, head back the way you came back to the Shadow Canyon junction and continue straight/left to Bear Peak. Continue on the trail to the north side of the Bear Peak summit block and scramble up to the top of Bear Peak. Backtrack to the west side of the mountain and take the Bear Peak West Ridge trail down some steep rocky switchbacks which eventually give way to buff, perfect singletrack.

Motor along the flowing trail down to Bear Canyon, where you cross a reliable creek. Shortly after the creek, make a sharp left up the Green-Bear trail and head up winding and generally smooth trail to the summit of Green Mountain. From the summit of Green Mountain, head back down to the west and take the Ranger Trail to the north. After a few steep switchbacks, the trail turns to smooth and wide singletrack that can be easily bombed down.

At the Gregory Canyon junction, go left up a short ways up to Flagstaff Road. Cross Flagstaff road and take the Ute Trail just to the left of the gate in the parking area. Follow the Ute Trail for a few minutes. To tag the true summit of Flagstaff, head off trail to the left to the highest point you can find - a molar shaped boulder. From the summit, head north back to the Ute Trail and the Flagstaff Amphitheater area (bathrooms nearby). Take the Flagstaff Trail down for a little over a mile. The trail crosses the road several times and also intersects many climbing access trails, so be careful to stay on the correct trail. The trail crosses Flagstaff road one more time at the Panorama Point parking area.

From here, take the Viewpoint Trail north from the parking area as it descends easy and fast trail down to Boulder. Where the trail ends, take a short dirt road to a roundabout and enter Eben G. Fine Park. Follow the creek path West to an underpass (drinking fountain and bathrooms nearby). Cross under Canyon Blvd. on the bike path up to the Settlers Park Trail. Follow the system of trails north. If you go left, it will take you the easy way over a short hill. If you go right, you'll pass through the Red Rocks rock formation.

(From here you can go out and back to the summit of Anemone Hill to the West. Typically this isn't included in the Skyline Traverse)

Drop down the other side of the hill and into the Centennial Trail parking area. Cross Mapleton road and go to the Sanitas picnic shelter, then left onto the Mt. Sanitas Trail. Climb 1.3 miles of steep, rocky terrain to the summit of Sanitas, finishing the Skyline Traverse. From the summit, the fastest way is to go back the way you came, although you can also go to the East and take the East Ridge Trail and then the Sanitas Valley Trail back down to Mapleton Road, which is a half mile longer.


Shared By:

Eli Zabielski

Trail Ratings

  4.7 from 139 votes


in South Mesa


  4.7 from 139 votes
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289 Views Last Month
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Sunrise from Mt Sanitas
Nov 3, 2017 near Boulder, CO
The "sighting disc" at the top of Green Mountain.  Line up the pins so you know what mountain you're looking at.
May 3, 2015 near Boulder, CO
Bear Peak panorama
Jun 27, 2015 near Boulder, CO
Devils Thumb seen from Towhee trail with permission from ottomandude
Jan 8, 2015 near Boulder, CO
Jan 7, 2024 near Boulder, CO
The Continental Divide from Bear Peak in Boulder, CO
Aug 17, 2019 near Boulder, CO


Current Trail Conditions

Minor Issues 52 days ago
Add Your Check-In


Mar 1, 2024
Jules B
Parked at Shanahan and took the Skip bus back. Traction helpful up Shadow, ice in shady areas, S. Boulder was snowy and the descent down Green icy. 21mi — 7h 45m
Mar 1, 2024
Jules Barkweiss
Parked at shanahan, traction helpful up Shadow, S. Boulder snowy, water in river after Green Peak. Great day 20.8mi — 7h 45m
Oct 14, 2023
Chelsea Anglin
Oct 8, 2023
Anneke Kakebeen
Did long canyon by accident
Sep 21, 2023
Chelsea Anglin
Aug 29, 2023
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Aug 14, 2023
Haley Wintsch
Jul 13, 2023
Jules B
Parked at Shanahan Ridge and ran up Shadow Canyon, completed the traverse then took the Skip bus back to my car. Filled water at Foot of the Mtn motel 20.1mi — 7h 16m

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