Numerous formations in the Flatirons are closed to climbing every year from February 1 – July 31 to protect birds of prey. The closures have been in place for decades and have helped falcons, eagles, bats and other bird species reproduce and raise young without disruption and restore populations. The formations are monitored for nesting activity by OSMP staff and volunteers and closures dates may change. Trails can also be closed for construction and repairs, which may affect access to climbing formations.

The following raptor closures were lifted on May 15, 2018:

  • Mount Sanitas Summitsouth of the Mt. Sanitas East Ridge Trail, east of Mt. Sanitas Trail (both trails remain open)
  • Skunk Canyonincluding Ridges 2, 3 and 4, the Aechean Pronouncement, the Dreadnaught, the North Ridge and the entirety of Sacred Cliffs.
  • Der Freischutz, Frankenstein’s Castle, The Bubble, Der Freischutz, Southern Dinosaur Egg, Northern Dinosaur Egg and  Dinosaur Rock.
  • Bear Creek Spire: north of Bear Canyon Trail (the designated Bear Canyon hiking trail remains open).
  • The Kolb, Weiser and ERTL Properties east of 75th Street and north of Valmont Road.

The following formations are closed from February 1 – July 31, 2018:

The following formation will remain closed past July 31, 2018:

  • Third Flatiron, including the 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. OSMP recognizes this closure extension will impact climbers’ access to the Third Flatiron and encourages them to visit for updates on when the closure will be lifted. Information on OSMP wildlife closures, which help to protect sensitive habitats, can be viewed at

For a complete list of trail and raptor closures and the most up-to-date information, please visit the OSMP sites: