Trail and Area Closures and Advisories

Open Space and Mountain Parks (OSMP) makes every attempt to keep this page as up to date as possible. However, some closures and trail advisories are made on an emergency basis for the safety and well-being of our visitors, wildlife and natural resources. Please watch for these signs during your visit. Accessing closed areas can result in a summons with penalties up to 90 days in jail and/or a $1,000 fine.

Temporary Closures, Advisories and Fire Bans

Muddy trail closures

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

Other Trail Closures and Advisories

Flatirons Vista Trailhead one-day closure April 24
The trailhead will be closed from 6 am - 5 pm on Wednesday, April 24 for maintenance and repair. Trails in the area will remain open unless closed for muddy trail conditions.

South Boulder Creek Trail section closed beginning March 11
Starting as early as Monday, March 11, OSMP will start a two-month ecological restoration project to improve fish habitat along South Boulder Creek north of South Boulder Road. A section of the unpaved South Boulder Creek Trail between Bobolink Trailhead and the East Boulder Community Center will be closed during the project. Community members will still be able to access the unpaved trail south of the Bobolink Trailhead but will need to detour back onto the paved South Boulder Creek Trail to continue south toward the bridge. The paved South Boulder Creek Trail will remain open except for two to four days in late March when OSMP will close the trail for additional work needed for the restoration project in South Boulder Creek.

East Boulder - Gunbarrel Trail intermittent closures beginning March 11
A portion of the East Boulder - Gunbarrel Trail will be closed from 8 am to 5 pm, Monday through Friday, beginning Monday, March 11 for construction of the new Vesper Trail. The trail will be closed from the Boulderado and Cambridge Access Point and extending about 1 mile east. More information can be found on the Vesper Trail Construction and Ecological Restoration project page.

Eagle and Sage Trails Repair Project ongoing
The Eagle Trail & Trailhead are now open. A section of the Sage Trail is closed from 7 am - 5 pm, Monday through Friday to conduct maintenance and repair work. More information is available on the Eagle Sage Repairs project page.

North Sky Trail construction impacts
The area north of Foothills North Trail between Hogback Ridge and US 36 is closed for construction of the North Sky Trail. Closures of that section of Foothills North Trail and the Foothills Trailhead will begin again in late-February. More information is available on the North Sky Project page.

Sawhill Ponds closure
Sawhill Ponds east of Boulder is closed for a multi-year project to improve the city’s main sanitary sewer line. These seasonal closures are intended to help expedite project work and protect wildlife from disturbances and will be in place through late-May 2024. Sawhill Pond closures may also be required this fall and next year, depending on construction progress this fall/winter season.

Boulder Star Area Closure
The City of Boulder reminds everyone to view the Boulder Star from afar as it remains closed. No designated trail currently leads to the Boulder Star. Learn more about viewing the Boulder Star from afar.

Marshall Fire-related trail restrictions
On-trail-use-only regulations in the Marshall Mesa area continue to be enforced as the area has changed since the Marshall Fire and hazards may be present. Some properties affected by the Marshall Fire remain closed while staff monitor ongoing ecological and agricultural needs on those properties.

Creek Closures to Limit Spread of Invasive Mudsnails Instituted
The City of Boulder has closed access to South Boulder Creek at the South Mesa Trailhead to prevent the spread of a highly invasive aquatic species, New Zealand Mudsnails (NZMS). The South Mesa Trailhead and the Mesa Trail will remain open. Learn more about the NZMS closures.

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.

Current Area Closures

The area closures below do not close any designated hiking trails (climbing access trails may be affected). Please be sure to check for any leash restrictions if you are bringing a dog. Current area closures can be seen on the Wildlife Closures map.

Bald Eagle Closures Nov. 1 - July 31

The areas below are closed from Nov. 1 to July 31 for the protection of nesting and roosting Bald Eagles:

Golden Eagle Closures Dec. 15 - July 31

The areas below are closed from Dec. 15 to July 31 for the protection of nesting Golden Eagles:

  • Lefthand Canyon Palisades, at the intersection of Lefthand Canyon Drive and Olde Stage Road (Buckingham Picnic area remains open).
  • Skunk Canyon, including Ridges 2, 3 and 4, the Aechean Pronouncement, the Dreadnaught, Hippo Head, the North Ridge and the entirety of Sacred Cliffs.

The following closure was lifted early:

  • Lifted 4/10/24: Flagstaff Mountain, the north side of Flagstaff Mountain. The Boy Scout Trail remains open.

Falcon Closures Feb. 1 - July 31

Thanks to OSMP visitors and volunteers for supporting these closures and the cliff-nesting raptor program! The following areas (listed north to south) are closed from Feb. 1 - July 31 to protect falcons:

  • Third Flatiron, including Queen Anne’s Head, W.C Fields Pinnacle, 1911 Gully and the Ghetto, the East Bench & West Bench, the East & West Ironing Boards, The Fin, Green Thumb and Jaws.
  • The Back Porch and The Box
  • Fern Canyon, north of the Fern Canyon Trail, including the Nebel Horn Ridge, East Ridge, the Goose and the Goose Eggs (the designated Fern Canyon hiking trail remains open).
  • The Sphinx
  • The Apostle
  • Shadow Canyon and the Matron: The Maiden remains open and accessible from the east; Shadow Canyon Trail remains open.
  • The entire Mickey Mouse wall, including South Tower, North Tower, Central Tower, Ship's Prow, Wall of Shiva's Dance, The Gargoyle, the East Face and Cryptic Crags.

Please note: Golden Eagle closures now begin on Dec. 15.

Burrowing Owl Closures March 15 - Oct. 31

Thank you for your cooperation in respecting the closures and providing the owls a quiet place to nest!

These areas are closed to protect nesting burrowing owls every year from March 15-Oct. 31:

This Parks and Recreation property will be closed through Oct. 31 if burrowing owls nest in the area:

  • Boulder Reservoir (Dry Creek East): East of 51st/55th Streets, south of Dry Creek, west of the Boulder Reservoir water body and north of the private property on North 51st St.

All designated trails near these areas remain open to help visitors view wildlife species as they thrive in their native habitats.

Osprey, Northern Harrier & American Bittern Closures March 15 - Sept. 10

The following area on OSMP is closed every year from March 15 to Sept. 10 to protect nesting osprey and Northern Harrier:

  • Axelson: Part of the Axelson property near the Boulder Reservoir is closed from March 15 to Sept. 10 every year to protect nesting osprey.
  • Boulder Valley Ranch: West of 51st/55th, west of Eagle Trail and west of the Boulder Valley Ranch pond.
  • Sawhill Ponds: The southwest corner of the Sawhill Ponds property, located west of 75th St. between Valmont and Jay.

The following areas on Parks & Recreation land are closed every year from March 15 to Sept. 10 to protect nesting osprey, northern harrier and American bittern:

  • Boulder Reservoir (Little Dry Creek East): East of 51st/55th Streets, south of private property on North 51st St., west of the Boulder Reservoir water body and north of the Boulder Reservoir Regional Park entrance.
  • Boulder Reservoir (Little Dry Creek West): West of 51st/55th Streets, south of the Eagle Trailhead, east of Boulder Valley Ranch and north of private property on Valhalla Drive.
  • Boulder Reservoir (Dry Creek East): East of 51st/55th Streets, south of Dry Creek, west of the Boulder Reservoir water body and north of the private property on North 51st St.
  • Coot Lake: Within the wooden fence that surrounds the western portion of the Coot Lake area.

All designated trails near these areas remain open to help visitors view wildlife species as they thrive in their native habitats.

Bat Roosting Site Closures - Year-Round & Seasonal

Female bats locate roosting sites in caves and rock crevices along the foothills, where the pups are raised in maternity colonies. The pups suffer high mortality rates even under normal conditions, so these closures help ensure they will remain undisturbed by humans during roosting season. Thank you for your cooperation!

Permanent closures:

The following areas are closed permanently to human use to reduce the chance of people introducing White-Nose Syndrome.

Seasonal closures:

  • Closed April 1 - Sept. 1: the east face of the climbing formation known as Der Zerkle is closed April 1 - Sept. 1 every year.
  • Closed April 1 - Oct. 1: A buffer surrounding Mallory Cave is closed April 1 - Oct. 1 to protect Townsend’s Big-eared Bats. Instead of being part of the permanent Mallory Cave closure, the climbing routes on the east face of The Hand, the standard route on the Finger Flatiron, and all of Shark’s Fin are only closed from April 1 to Oct.1.

New Zealand Mudsnail Closures


Learn more about New Zealand Mudsnails and how you can help stop the spread.

Inactive Closures

The closures listed below are not currently in place. You may review the maps for reference, but these areas are not currently closed.

Seasonal Leash Restrictions Aug. 15 - Nov. 1

These areas are frequent foraging locations for bears. Leash restrictions protect dogs and their guardians when there is a high probability of encountering bears, and help avoid disturbing bears while they feed during the critical pre-hibernation period.

Seasonal Leash Restrictions are in place Aug. 15 to Nov. 1.

Due to bear activity dogs must be leashed from 8-15 to 11-1 on the following trails:

Grassland Ground Nesting Bird restriction in place May 1 to July 31

The Greenbelt Plateau area is also affected by a seasonal leash restriction for grassland ground nesting birds from May 1 to July 31 every year: Both sides of the Greenbelt Plateau trail from the Community Ditch trail to the Greenbelt Plateau trailhead on Highway 128. Dogs must be on-leash on the Greenbelt Plateau trail, view map.

Grassland Ground Nesting Bird Closures May 1 - July 31

Grassland breeding birds have seen widespread and precipitous declines at a continental scale due to a variety of impacts. OSMP provides habitat for several species of grassland nesting birds including Grasshopper Sparrow, Western Meadowlark, Vesper Sparrow, Horned Lark, Lark Sparrow, and Savannah Sparrow. OSMP closes certain areas to help reduce human impacts that could disturb nesting birds.

These closures do not affect designated trails in the area which remain open throughout the closure period.

The following areas are closed May 1 - July 31 every year:

  • Greenbelt Plateau: Both sides of the Greenbelt Plateau trail from the Community Ditch trail to the Greenbelt Plateau trailhead on Highway 128. Dogs must be on-leash on the Greenbelt Plateau trail;
  • Doudy Draw: the area north of Community Ditch trail and west of Highway 93;
  • Flatirons Vista: the area north of Flatirons Vista North trail and west of Highway 93 on top of the mesa; and
  • Lower Big Bluestem: the area north of the South Boulder Creek West Trail, east of the Bluestem Connector and south of Shanahan Ridge (dogs are prohibited off-trail in this area year round).
  • Hester, DeLuca and Campbell properties: located north of Nimbus Road and west of 39th Street.

Note: Dogs must be on-leash on Lower Big Bluestem year round due to West Trail Study Area Implementation.