Hiking Project Logo

Mount Sanitas Loop

 4.1 (84)


3.2 Miles 5.2 Kilometers

1,281' 390 m


-1,280' -390 m



Avg Grade (9°)


Max Grade (23°)

6,780' 2,067 m


5,521' 1,683 m


Shared By Nick Wilder


All Clear 12 days ago
~20 ft dirt-covered snow on East Ridge segment, easy to avoid by walking on rocks. Also ~30ft mud at top of valley trail. History

Getting forecast...

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

Nick Wilder

Dogs Off-leash

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.


You & This Featured Hike

Rate Quality

   Clear Rating

Rate Difficulty

Share This Hike

Your Check-Ins


Dec 12, 2018
Adrianna Carey
Challenging, short, fun. Very few icy spots. 3.2mi
Dec 2, 2018
Emily Goodin
3.2mi — 1h 10m
Nov 20, 2018
Maria Lopez Ruiz
Nov 15, 2018
Blake Pemberton
Oct 19, 2018
Holly Whitmore
Oct 11, 2018
Eric Zdanowski
Oct 7, 2018
Nick Graham
Oct 5, 2018
Amy Nguyen

Trail Ratings

  4.1 from 84 votes


  4.1 from 84 votes
5 Star
4 Star
3 Star
2 Star
1 Star


in Colorado


331 Views Last Month
11,122 Since Nov 15, 2014
Intermediate/Difficult Intermediate/Difficult



Hiking Project is part of the REI Co-op family,
where a life outdoors is a life well lived.

Shop REI Hiking