Important Updates:

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Temporary Closures, Advisories and Fire Bans

Trail Map

Open Space and Mountain Parks (OSMP's) interactive trail map includes trail closures - an easy option to check before your trip!

OSMP Alerts

Winter conditions 

Winter conditions exist across open space! 

  • Trails may be icy & slick. 
  • Wear appropriate gear, such as traction devices for your shoes/boots.
  • Do not walk on ice-covered lakes and ponds.


People enjoy open space for physical, emotional and mental health. Remember to always be courteous. Don't forget: 

  • Only recreate with household members.
  • Wear a face covering when passing others. 
  • Stay on trail/walk through mud. Avoid stepping on vegetation. 
  • Visit 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.

Boulder Star closure

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

Muddy Trail Closures

Text “OSMP” to 888-777 to sign up for text updates about muddy trail closures.

OSMP Closed Trails
Muddy trail closures as of Monday April 12, 2021.

No trails are currently closed due to muddy conditions.


Other Trail Closures and Advisories

South Mesa Trailhead temporary closure Apr. 14, 2021
The trailhead will be closed to vehicles for maintenance work from 6 am to 5 pm on Wednesday, Apr. 14. Trails in the area will remain open. 

Royal Arch Trail temporary closure Apr. 12-16, 2021
OSMP will close the Royal Arch Trail starting as early as Monday, April 12, to conduct the repairs along the trail. The trail will be closed from Monday, April 12, through Friday, April 16 – weather permitting. This closure will be in place for 24 hours a day. OSMP requests visitors follow trail closures so department trail crews can work safely in Royal Arch’s steep terrain. 

Cottontail Trail closure starting as early as March 17, 2021
Starting as early as Wednesday, March 17, OSMP will temporarily close two sections of the Cottontail Trail – a part of the Longmont-to-Boulder Regional (LOBO) Trail northeast of Boulder – to conduct trail resurfacing and other maintenance work along the trail. A half-mile section of the Cottontail Trail south of State Highway 52 to the Boulder White Rock Ditch will be closed from 8 a.m. to 4:30 p.m. while this work occurs. This closure is expected to be in place for four weeks – weather permitting. When this closure is in effect, cyclists can reconnect with the LOBO Trail by using:

  • State Highway 52 to 71st Street to Lookout Road.
  • North 79th Street to Lookout Road

Additionally, a section of the Cottontail Trail that heads directly south of the Boulder White Rock Ditch east of the Gunbarrel Estates neighborhood will be closed during the entirety of the project. The closure of this section of trail will be in place 24 hours a day and will continue until July 30 – weather permitting. OSMP will have signs in place to direct visitors around trail repairs.

South Boulder Creek access closure between South Boulder Road and Marshall Road beginning Oct. 29, 2020
Access to South Boulder Creek between South Boulder Road and Marshall Road is temporarily closed to help prevent the spread of invasive New Zealand mudsnails (NZMS). Please visit NZMS page for details. The South Boulder Creek Trail remains open.

Boulder Star closure to remain in effect this winter
Oct. 20, 2020: OSMP will continue the existing closure around the Boulder Star area on Flagstaff Mountain and will replace temporary fencing with reinforced wood fencing in the area. These actions seek to help restore vegetative growth in the mostly barren Boulder Star area and come amid ongoing safety and ecological concerns, along with COVID-19 precautions to discourage large group gatherings. No designated trail currently leads to the Boulder Star area, which sees large gatherings during the winter. The star is located on steep terrain that has sustained significant plant and erosion damage because of increasing visitation – leading to numerous wildlife habitat disturbances. Learn more about the Boulder Star closure.

Flagstaff Summit Road closure beginning Oct. 25, 2020
The Flagstaff Summit Road is closed to vehicular traffic. The road is closed to vehicles every winter, but remains open to pedestrians. 

Anemone Hill Trail Construction beginning May 14, 2020
Please visit for details on this project and trail closures.

Gregory Canyon restroom closed 
The restroom is temporarily closed because of maintenance issues. This notice will be removed when the restroom has been reopened.

Chapman Drive and Boulder Falls impacted by work in Boulder Canyon
Visitor access to these areas – either by bike, by car or by foot – will be limited while the Colorado Department of Transportation conducts work in Boulder Canyon. For specific closure times, please visit the project website. Boulder Falls is currently open. Temporary closures will still occur until construction is complete. 

Rock Island 1 in Boulder Canyon closed
Rock Island 1 is closed. The rock fractured and part fell onto the Boulder Canyon Creek path. Sections of the remaining rock have been evaluated as unstable so it is closed until recommended bolting can be completed.   

No parking along Highway 170 near Doudy Draw and South Mesa Trailheads
Please remember that parking is not allowed on Highway 170 at any time.