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  • OSMP Trails & Recreation
  • OSMP Visitor Info
  • OSMP Get Involved
  • OSMP Nature & Restoration
  • OSMP - About
  • OSMP Kids & Families
  • OSMP Plans & Reports
  • OSMP en Español

Open Space and Mountain Parks

Open Space and Mountain Parks

Boulder's Open Space and Mountain Parks (OSMP) are a very special place. The open space lands teem with native plants and wildlife and are home to threatened and endangered species. They serve as a buffer between Boulder and nearby development. They sustain agriculture uses and add untold benefits to the natural environment - clean air, water, and earth.

The lands shape the urban mosaic of the Boulder Valley and provide residents with passive recreation opportunities. Trails are used by walkers, hikers, bicyclists, horseback riders, dog walkers and other passive recreational uses.

OSMP Alerts

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 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.

Trail/Trailhead Closures

Please see the temporary closures page for more details on the trail closures below. OSMP's interactive trail map also shows these longer-term trail closures and restrictions: 

  • Boulder Star area closure: The area around the Boulder Star is closed. 
  • South Boulder Creek access closure between South Boulder and Marshall Roads: Creek access is temporarily closed to help prevent the spread of invasive New Zealand mudsnails (NZMS). Please visit NZMS page for details.
  • Anemone Trail intermittent closures: Please visit for project and closure details. 
  • Gregory Canyon restroom closed: The restroom is temporarily closed because of maintenance issues.
  • Muddy trail closures: Please check the trail map or temporary closures page for any muddy trail closures.

Project Updates & Other Alerts

Annual Meeting on Prairie Dogs and Irrigated Agriculture Restoration: Open Space and Mountain Parks (OSMP) will host a virtual community meeting to discuss its prairie dog and agriculture management, conservation and restoration efforts on Monday, Dec. 14Learn more.

Tall Oatgrass Management Program: Grazing and its associated livestock fencing are an important part of a continuing OSMP restoration project to help contain tall oatgrass – a highly invasive, non-native grass – in the area. 

Purchase OSMP annual parking permits online: Visitors whose vehicles are registered outside of Boulder County can now purchase OSMP annual parking permits online. Learn more about parking permits

Open Space and Mountain Parks Calendar

Free, public Nature Hikes and Programs can be found at

Open Space Board of Trustees Meeting

@ 6 to 8 p.m.

The OSBT usually meets on the second Wednesday of every month. Please view the agenda for meeting information, including start time and location.

View main city calendar for all upcoming city events, or for more events like this

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Featured Projects & Pages

Boulder Area Trails App Logo

Boulder Area Trails App

The City of Boulder and 11 other agencies created a mobile trails application that provides access to all trail information in and around Boulder County.

Dog on a trail wearing Voice and Sight Tag

Voice and Sight Tags

Information on how to register for the Voice and Sight Tag Program or renew your dogs' Voice and Sight Tags.

Volunteers in the field

Science at OSMP

Learn about the science being conducted by OSMP and independent researchers.

Sample from data explorer

Visitation Data Explorer

OSMP's Visitation Data Explorer provides a dynamic interface for exploring current data from our fleet of long-term trail counters.

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Interactive Trail Map