Summary
Project Description
The Federal Highway Administration–Central Federal Lands Highway Division (FHWA), in cooperation with the Marin County Department of Public Works (Marin County), the National Park Service, and the California Department of Parks and Recreation, is proposing to improve a segment of Muir Woods Road in Marin County. Muir Woods Road is also known as Frank Valley Road. Muir Woods Road is a narrow, two-lane, rural roadway that connects the Muir Woods National Monument to California Highway 1. The road is owned and maintained by Marin County and it serves as the primary access route to Muir Woods National Monument. The road also provides access to the Mount Tamalpais State Park, which is managed by the California Department of Parks and Recreation, Golden Gate National Recreation Area, and to the Panoramic Highway. Proposed improvements to Muir Woods Road include resurfacing, restoring, and rehabilitating the roadway; stabilizing slopes; and replacing the existing bridge over Redwood Creek.
Review type
Mitigated Negative Declarations (MND), Initial Study (IS)Status
Location
Muir Woods Road, from the entrance of Muir Woods National Monument to the intersection with Highway 1.
Applicant
Rachel Calvert , Senior Civil EngineerNotice of Availability
The Marin County Department of Public Works completed a Draft Initial Study/Mitigated Negative Declaration (IS/MND) for the Muir Woods Road Improvement Project. The Draft IS/MND is linked below in the "Environmental Review Documents" section near the bottom of this webpage. The 30-day public comment period on the adequacy of the Draft IS/MND began on April 22, 2026 and was extended to May 19, 2026.
This Draft IS/MND was developed to meet Marin County’s obligations as the lead agency under the California Environmental Quality Act (CEQA) and Marin County’s Environmental Impact Review Guidelines. Marin County’s role as CEQA lead agency is limited to state environmental review and does not constitute authorization of construction activities or impacts addressed under federal law. Marin County is responsible for providing technical information and data to FHWA. Marin County is also responsible for reviewing plans and environmental documents for purposes of CEQA compliance and coordination with FHWA. The National Park Service and the California Department of Parks and Recreation, as CEQA responsible agencies and the agencies responsible for managing lands surrounding Muir Woods Road, have been involved in all aspects of planning for the Muir Woods Road Improvement Project. FHWA is the lead federal agency for compliance with the National Environmental Policy Act (NEPA) and has prepared an Environmental Assessment (EA) concurrent with preparation of Marin County’s Draft IS/MND to support environmental compliance requirements for the Proposed Project. The EA is linked below in the "Environmental Review Materials" section near the bottom of this page.
A Response to Comments document was prepared to address the written comments received during the public comment period and is included in the revised Draft IS/MND, also linked below in the "Environmental Review Documents" section of this webpage.
On October 20, 2026, a hearing was conducted by the Marin County Board of Supervisors where the IS/MND was approved in addition to the associated project. A Notice of Determination was filed for the IS/MND on October 26, 2026 and is also linked below in the "Environmental Review Documents" section below.
Public Notice
Environmental Review Documents
The documents in this list may not work with all assistive technology and are being remediated. For alternative formats, please email Tammy Taylor or phone 415-473-7873. To use the California relay service, dial 711.
- Muir Woods Rd - Draft IS/MND (4.76 MB) — The Draft Initial Study/Mitigated Negative Declaration (IS/MND) for the Muir Woods Road Improvement Project.
- Muir Woods Rd - EA (6.65 MB) — The Environmental Assessment (EA) for the Muir Woods Road Improvement Project.
- Muir Woods Rd - IS/MND and RTC (8.15 MB) — The revised Draft Initial Study/Mitigated Negative Declaration (IS/MND) for the Muir Woods Road Improvement Project that includes a Response to Comments for public comments received on the Draft IS/MND as Appendix A.
- Muir Woods Rd - Notice of Determination (0.58 MB) — The Notice of Determination (NOD) filed for the Muir Woods Road Improvement Project Initial Study/Mitigated Negative Declaration (IS/MND) on October 26, 2026.