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.
Temporary trail closures at Boulder Valley Ranch February 8, 2010
Until further notice, the Hidden Valley, Degge, Mesa Reservoir, and Cobalt trails are closed. The Eagle Trail is closed from the valley uphill to the west. The Sage trail is open. Closure information will be posted at trailheads.
Construction on Four Mile Creek Bikeway Connection to begin in January Please see Boulder County's press release for more information on this project.
OSMP to burn ditches throughout winter months Starting the week of January 9, 2009, OSMP, in conjunction with the Boulder Fire Department, will be conducting ditch burns throughout the winter months on the city’s agricultural properties. Burning is weather dependent, and no burning will occur on Red Air Quality days. Trained Fire Department personnel will be on site during this activity as well as natural resource advisors.
Boulder Falls temporarily closed March 30, 2009 Boulder Falls remains closed indefinitely, due to the danger of continuing rock falls in the area. Boulder Falls is located 11 miles west of Boulder on the north side of Canyon Boulevard (SR119) between Boulder and Nederland. The falls can be safely viewed from State Highway 119's right-of-way. No Trespassing signs have been posted in the area.
Prescribed burn and temporary trail closure Wednesday, September 16, 2009 - burn area closed.
OSMP and the Boulder Fire Department, in conjunction with other local fire agencies, conducted a prescribed burn on Shanahan Ridge on Sept. 16, 2009. The area burned is located east of the Mesa Trail and south of the Shanahan – South Fork Trail, and will remain closed until the area is safe for pedestrian travel. Signs will be hung at the burn site as well as in the trailhead boards in Shanahan Ridge, and on trail posts near the burn. The Shanahan – South Fork Trail was closed during the burn, but is now open. Map of closed burn area .
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.
Social Trail Restoration
Efforts are underway in the Eldorado/Doudy Draw and Marshall Mesa/Southern Grassland areas to restore social trails. Please observe the "Keep off the trail" signs and avoid traveling on these social trails and eroded sites that are being restored. "Social trails" are often unsustainable and result in the trampling of fragile vegetation, soil compaction and erosion and disturbance to wildlife.
Wildland Restoration Volunteers working in Eldorado/Doudy Draw Click here to see more photos of the project!
The following areas will be closed for the protection of grassland ground nesting birds from May 1 to July 31:
both sides of the Greenbelt Plateau Trail from Community Ditch trail to Highway 128. Dogs will be allowed on the Greenbelt Plateau Trail only if they are on-leash (area is normally voice and sight control);
Community Ditch Trail west of Highway 93 and north of Community Ditch Trail;
Seasonal Bat roosting site closures in effect April 1
OSMP closes Mallory and Harmon Caves, accessible from NCAR trailhead at the end of Table Mesa Road from April 1 to October 1 of every year. They are closed to protect Townsend's Big Eared bats. OSMP also closes the east face of Der Zerkle rock formation, accessible from the NCAR trailhead from April 1 to September 1 to protect the roosting sites of Fringed Myotis bats.
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 seasonal closures help ensure they will remain undisturbed by humans during roosting season. Thank you for your cooperation!
OSMP closes the Kolb property in the White Rocks area (near 75th and Valmont) and the Coal Creek Property (east of Hwy 93 and near Marshall Lake) temporarily between Nov. 1 and July 31 to protect bald eagle nesting and roosting activity.
The following areas are closed every year from Feb. 1 - July 31 to protect cliff nesting raptors:
Back Porch-Skunk Canyon and Sacred Cliffs: Skunk Canyon, Ridge 2 and all areas west of Ridge 2; Sacred Cliffs, south rib of Green Mountain, and the Back Porch are closed.
Gregory Canyon Amphitheater: Amphitheater Express Trail and the 3rd Pinnacle are closed. The 4th and 5th Pinnacles and the Amphitheater Trail to Saddle Rock remain open.
The entire Third Flatiron:all routes, including: The Descent Trail, Queen Anne's Head, W.C. Field's Pinnacle, 1911 Gully, The Ghetto, The East and West Ironing Boards, The Fin, Green Thumb, and Jaws are closed.
Shadow Canyon:The Matron: all areas within 1/4 mile radius, the entire Devil's Thumb Ridge, Towers of the Moon, Elephant Rock, Jamcrack Spire and Diamond Head are closed. The Maiden is OPEN to climbing with access from the EAST side only.
OSMP is working at the Doudy Draw Trail (between the parking lot and the picnic area). Rock will be removed from the outside of the trail, and replaced with other support; three pull outs will also be installed to improve passing opportunities on the trail. The work will include heavy equipment in the area, and may include cutting the fence around the parking lot. At this time the trail remains open, when the work necessitates closing the existing trail, a temporary trail will be created for visitor use. The work is expected to take approximately 10 weeks.
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Open Space & Mtn Parks 
Respecting all area closures.
