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Muir Woods Road

Project Description

Muir Woods Road is a narrow, two-lane rural roadway owned and maintained by Marin County, California. The road connects CA 1 from the south to Muir Woods National Monument. The road is used by vehicles, buses, and trucks to access the National Monument or to travel to the Panoramic Highway. The road has a functionally deficient bridge across Redwood Creek.

FHWA-CFLHD, in cooperation with Marin County, the National Park Service (NPS), and California State Parks are proposing to improve road conditions along a segment of Muir Woods Road. An Environmental Assessment (EA)/Initial Study (IS) is in process under the National Environmental Policy Act (NEPA) and California Environmental Quality Act (CEQA) to evaluate potential road rehabilitation improvements to 2.42 miles of Muir Woods Road (Route County Road 107) in Marin County.

More additional information about the project, visit the National Park Service website and the Marin County website.


The purpose of the proposed action is to restore the structural integrity of the road, enhance safety for all users accessing state and federal lands, correct road-related drainage problems, reduce water quality impacts to Redwood Creek, and reduce on-going road maintenance requirements. The purpose of the bridge project is to replace the Muir Woods Road Bridge over Redwood Creek, which was constructed in 1946 and does not meet current bridge standards.


The project is needed because Redwood Creek has eroded and undermined roadway embankment slopes in several locations. In some areas of slope failure, the road has been reduced to one lane. Pavement along the road is heavily damaged due to poor drainage and many areas have severe alligator cracking, deteriorated edges, and low shoulders. Existing road widths are substandard, varying from 18 feet to 24 feet. The narrow lane widths make it difficult for vehicles to safely pass bicyclists. The undermined road and vehicles driving or parking off-road have damaged riparian vegetation, which has led to increased sedimentation entering Redwood Creek. The bridge project is needed because the aging structure has bridge footings that are exposed, the concrete is deteriorating, and corroded rebar is exposed.

Anticipated Timeline

  • Release of Environmental Assessment (EA): Fall 2020
  • Anticipated Release of Environmental Decision Document: Summer 2021
  • Advertise: Winter 2025
  • Construction: Spring 2026 - Spring 2027

Project Photos