Muir Woods Road Bridge Replacement Project

Rosemarie Gaglione, Director, Public Works
Muir Woods Road Bridge

Project Description:

UPDATE 11/30/18: The County of Marin received federal funding to replace local bridges that were identified as structurally deficient and functionally obsolete. Muir Woods Road Bridge over Redwood Creek was one of the bridges identified for replacement and a project was initiated in 2015 to conduct environmental studies and to begin design work. Protecting the riparian habitat, safeguarding the adjacent Golden Gate National Recreation Area and State Parks, and maintaining traffic are high priorities for the project.

Muir Woods Road Bridge is located just west of the entrance to Muir Woods National Monument. Muir Woods Road is a two-lane roadway that provides connectivity between Muir Beach, Mill Valley and the park lands. The existing bridge was built in 1946 and is a single-span, reinforced concrete T-beam structure. The bridge needs to be replaced for the following reasons:

  • The structure has deficiencies in the structural concrete and structural steel.
  • The existing bridge alignment does not meet current road geometry standards.
  • Bridge railings do not meet current safety standards.
  • Scour from the creek has caused undermining of the structure.

The project improvements are anticipated to extend from 400 feet west of the bridge to 600 feet east of the bridge along Muir Woods Road which will involve realigning the roadway to correct the current “S” curve. Access to the Muir Woods National Monument will be maintained at all times.

Please note: This project has now been incorporated with the Muir Woods Road Rehabilitation Project which is being implemented by Federal Highway Administration, Central Federal Lands Division. For more information please visit the National Park Service page.

The anticipated project timeline is as follows:

Summer, 2015
Begin Environmental Studies and Preliminary Engineering
Fall, 2016 / Summer 2017
Community Outreach
Spring, 2017
Initiate Environmental Assessment
Summer, 2018
Transfer Bridge Funding into Road Rehab. Project
Fall, 2019
Conclude Environmental Assessment & Permitting
Fall, 2019
Initiate Detailed Design
Fall, 2019 Initiate Right-of-Way
Spring, 2022 Begin Construction


Community outreach and engagement are fundamental to developing the design of the new bridge. The project development process will integrate the community’s vision and resident needs so that they are reflected in the final design. Public meeting(s) will be scheduled and advertised at a later date.

Stay Informed:

For more information, contact Philip Buckley, Associate Civil Engineer.