MILL VALLEY / MARIN COUNTY, Calif. Caltrans is warning drivers to expect occasional closures of the connector from northbound US-101 to northbound State Route 1 near Mill Valley when water reaches the ramp during unusually high tides. The agency’s November 3 notice says the lower half of the Manzanita Park and Ride lot remains closed because of flooding.
Is the ramp closed all week?
No. Caltrans says maintenance crews will close the connector when tidal flooding affects the roadway, and reopen it once conditions permit. Shoulder parking along SR-1 may also be affected. A predicted high-tide window is not itself a scheduled full-week highway closure.
When are higher tides forecast?
The agency lists the next king-tide period as November 22–28, 2026, with later periods December 20–27, January 18–24 and February 16–22. Flooding is also possible outside those dates when weather, rainfall and tide conditions combine. The connector was affected repeatedly October 29–31, including several hours of disruption on October 29.
How drivers and pedestrians can prepare
Check the current status using Caltrans QuickMap or regional traffic information before traveling. Do not attempt to drive through floodwater, even if it looks shallow. Drivers relying on the Manzanita commuter lot should verify which spaces are accessible.
The tide warning is especially relevant to commuters moving between Highway 101, Shoreline Highway and the southern Marin coastline. Those planning coastal trips should allow alternate routing rather than assume the connector is always available.
Source: Caltrans District 4, November 3, 2026.
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