Muir Woods is open all year round. The park closes an hour before sunset. I think the schedule in the fall is 9:00 a.m to 5:00 p.m
Like the previous person responded, they are open. But they only take reservations for parking and is required so be sure to make your parking reservation before you go. And they also booked up pretty quickly so the sooner the better
It open on Thanksgiving and all major Hollidays.
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