Mount Sanitas Trailhead
Boulder Star area on Flagstaff Mountain is closed
The Boulder Star area on Flagstaff Mountain IS CLOSED to prevent gatherings amid the COVID-19 pandemic and because of ecological and safety concerns in the area. Visitors entering the Boulder Star closure area on Flagstaff Mountain can face up to a $1,000 fine or 90 days in jail. Learn more. Follow these other important recreation guidelines:
- Stay home if you are sick or exhibiting COVID-19 symptoms.
- Only recreate with members of your own household.
- Always bring a face covering. Wear it when you can’t maintain 6 feet of physical distance.
- Keep the space in open space! Always stay at least 6 feet from non-household visitors.
- Visit OSMPTrails.org to see current trail closures, historical data that shows areas of high and low open space use and trails that are wider than 6 feet. See when trails are busiest through our Visitation Data Explorer.
- Protect first responders. Know your limits and don’t take unnecessary risks.
0.5 mile west of 4th Street on Mapleton Avenue.
Please check for Trail & Area Closures.
You are responsible for knowing and complying with all closures and OSMP rules & regulations.
Parking is available in the Centennial Trailhead on the south side of Mapleton Avenue.
Please keep your car doors locked and your car windows rolled up at all times while leaving your vehicle parked at OSMP trailheads. Also consider leaving important valuables at home or take them with you while visiting open space. To report suspicious activity please call City of Boulder Dispatch 303-441-3333 or Boulder County Dispatch 303-441-4444. For crimes in progress, call 911 immediately.
Sanitas Valley Trail is a wide, graveled trail heading north up the valley between the Hogback Ridge and Mount Sanitas. It affords access to the Dakota Ridge Trail to the east, the Mount Sanitas Trail to the west, the Hawthorne Trail near its northeast terminus, and the East Ridge Trail at its northwest terminus. It is heavily utilized by people walking their dogs.
Mount Sanitas Trail is a moderate to difficult trail which meanders both sides of the ridge leading to the summit of Mount Sanitas. The southern portion of the trail is utilized as an access by climbers to several bouldering areas along the trail. Access points to these bouldering areas are clearly marked and we ask your cooperation that you only boulder in designated areas. This trail also provides beautiful views to both the east and west.
Dakota Ridge Trail meanders the west side of the Dakota Ridge through ponderosa pine stands. It is heavily utilized by runners. Hawthorne Trail is a steep and difficult trail leading down a narrow gully before leveling to a more moderate incline. Its terminus is at the access just west of Fourth Street on Hawthorne. East Ridge Trail connects the Sanitas Valley Trail to the Mount Sanitas Trail at the north end of the mountain. It is steep and difficult.
Lion's Lair Trail connects Mount Sanitas summit to two different access points on Sunshine Canyon Drive west of the Centennial Trailhead. The trail is not as steep and difficult as the Mount Sanitas Trail.
Centennial Trailhead, which is just west of the Sanitas Trailhead, accesses the Red Rocks Trail and Anemone Hill Trail. Both trails go south from the trailhead. The Red Rocks trail is 0.6 miles and gains 300 vertical feet. The trail climbs to a ridge, then to the fins of the Red Rocks. After it passes a historic marker, the trail ends at Settlers' Park. Anemone Hill Trail climbs 0.4 miles up the hill west of the Red Rocks.
An RTD bus passes very close to this trailhead. Learn about Taking the Bus to OSMP.
Restrooms are available at the Centennial Trailhead.
Three picnic tables and a small pavilion are available. Grills and stoves are prohibited.
No bicycles are allowed in this area.
Learn about bringing your dog to OSMP. All dogs must be leashed in the Trailhead Leash Area. Beyond the trailhead, dog control requirements vary from trail to trail, so carefully watch for dog regulation signs at trailheads and trail intersections. On most OSMP trails in this area, dogs must be on a hand-held leash at all times unless they meet the voice and sight control standard and display a City of Boulder Voice and Sight tag. Dog excrement removal is required by law. A dog station is available to aid in the collection of dog excrement.
Horses are allowed on most trails. On-trail riding is encouraged to protect rare plants and wildlife habitat. Learn more about riding your horse on OSMP.
Mountain lions inhabit this area. Coyotes, foxes, mule deer, and raptors are commonly sighted.
- Named for the sanitarium (health spa) that is now the Mapleton Medical Center.
- Sandstone quarried for original buildings on CU campus.
- Check out the self-guided Cultural Resources History Hike - Hiking in Mt. Sanitas.