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Project Overview

City of Boulder Open Space and Mountain Parks (OSMP) closed the Marshall Mesa Trailhead in late-October, 2024 to support state coal mine mitigation work and conduct extensive trailhead improvements. OSMP anticipates the trailhead will be closed for one year.

Most trails in the area remain open. A newly constructed interim trail – built with Boulder Mountainbike Alliance volunteers – has been installed to provide access for visitors arriving by bike and from the Colorado Department of Transportation parking lot at the intersection of Highway 93 and Marshall Road. Please visit OSMPTrails.org to see current trail closures and view alternate destinations.

State mitigation work in the Marshall Mesa area is expected to take four months to complete. Learn more about coal mine mitigation work. OSMP trailhead renovations – focused on improving visitor safety and outdoor experiences in the area – will occur afterwards and are expected to take about eight months to finish.

Project Trail Access 

During the Marshall Mesa trailhead closure, visitors can access most of the Marshall Mesa trails. Bicyclists also will be able to complete the full "Dirty Bismark" loop. View maps below. Visitors can access the Marshall Mesa area from these points:

  • A detour from a parking lot at Marshall Road and U.S. Highway 93.
  • The Community Ditch Trail starting from Doudy Draw Trailhead 
  • Greenbelt Plateau Trail starting from Greenbelt Plateau Trailhead or Flatirons Vista Trailhead (includes a restroom) 
  • Mayhoffer-Singletree Trail starting from 66th Street 
  • Pedestrians and bicyclists only from the Marshall Valley Trail intersection at Marshall Road (no vehicle parking) 
  • Coalton Trail starting from Boulder County Parks & Open Space's Coalton Trailhead (includes a restroom) 

View a larger area trail access map.

Map of open trails on Marshall Mesa

View a larger map of trail detour from the parking lot at Marshall Road and U.S. Highway 93.

Marshall Mesa will be accessible from parking lot via detour

Trailhead Improvements

Planned OSMP improvements at the Marshall Mesa Trailhead include:

  • Enhancing vehicle and shuttle access to and within the trailhead.
  • Improving parking to help support vehicle access to the trailhead.
  • Developing an accessible trail out of the trailhead to support visitors experiencing disabilities and mobility challenges.
  • Creating a trail connection to the RTD "Parks and Ride" crosswalk that links the Marshall Mesa trailhead and a parking area at the intersection of U.S. Highway 93 and Marshall Road.
  • Re-routing trails to support help vehicle and shuttle improvements.
  • Replacing the restroom, installing a shade shelter, increasing the number of bike racks, tables and benches in the area.
  • Installing new signage to help visitors connect to trails and support education and interpretation in the area.