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Mount Sanitas Loop

  4.1 ( 103 ) Favorite


3.2 mile 5.2 kilometer loop


Ascent: 1,281' 390 m
Descent: -1,280' -390 m
High: 6,780' 2,067 m
Low: 5,521' 1,683 m


Avg Grade: 15% (9°)
Max Grade: 43% (23°)


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Trail shared by Nick Wilder

Very popular and scenic loop right from the edge of town.

Nick Wilder

Features Views


This is a steep but rewarding trail, with great summit views of the foothils to the high peaks, and all of Boulder. It is virtually always crowded with all kinds of runners, hikers, and dogs.

Need to Know

In typical Boulder fashion, there are some crazy speed records on the various trails.


From the beginning of the Sanitas Valley Trail, take your first left on the Mount Sanitas Trail and immediately start the very steep ascent of the mountain. The trail is mostly shaded, but there are tons of high steps, both on logs and boulders, which make the trail tiring. You'll pass some large rock outcroppings that are popular with climbers and boulderers and several nice places to rest and enjoy the views both east and west.

After several false summits, you finally gain the true summit and have unobstructed views of all of Boulder to the east, and partially obstructed views of foothills and Indian Peaks to the west.

Head down the very steep East Ridge Trail, which has several tricky sections of steep rock. It eases up as you descend, and finally widens and becomes much easier as you get to a saddle and intersection with the Sanitas Valley Trail.

As you descend this nice, easy gravel road, enjoy the spectacular views of the Flatirons, seen from a unique side-on angle. You'll pass the historic Silver Lake ditch (which supplies water to Boulder farmers and has been in use since the late 1800's) and soon end back where you started.

Flora & Fauna

Mountain lions are common in the area, and the trail is occasionally closed if there is a fresh kill. You'd be lucky to see one though!

History & Background

The peak is named for the Boulder Sanitarium that sat at the current site of the Boulder Community Hospital. The building was completed in 1896 and was primarily used to treat tuberculosis patients. The original smokestack still stands.

There is also an old quarry halfway up the slope (a spur trail will lead you there) that was used for several early University of Colorado buildings.

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Family Friendly, ADA Accessible

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Sep 22, 2019
Lauren Castaneda
3h 00m
Aug 30, 2019
Sophia Pang
Aug 12, 2019
David Mata
Aug 12, 2019
Stephen Rocha
3.2mi — 1h 48m
Aug 10, 2019
Kevin O
Aug 5, 2019
Devon Kodger
whole thing in 3.2mi — 2h 40m
Aug 5, 2019
Neill E
The trail was quite challenging given the rapidity of the ascent. The trail down was very steep in places — 3h 00m
Aug 3, 2019
Ben Jenkins

Trail Ratings

  4.1 from 103 votes


  4.1 from 103 votes
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in Colorado


337 Views Last Month
15,554 Since Nov 15, 2014



Sunrise from Mt Saintas
Nov 3, 2017 near Boulder, CO
Beautiful descending views
May 15, 2015 near Boulder, CO
Wildflowers in the Spring
May 15, 2015 near Boulder, CO
The top of Mount Sanitas looks out at the beauty of Boulder and the Flatirons.
Apr 12, 2017 near Boulder, CO
Looking east from the summit at sunrise.
Dec 2, 2018 near Boulder, CO
Arriving at the summit, just missed the sunrise.
Dec 2, 2018 near Boulder, CO


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