Muir Woods Main Loop Trail - 2.5 Miles Round-Trip

Muir Woods is a remnant of ancient coast redwood forests that blanketed Northern California coastal valleys before the 1800s. William and Elizabeth Kent recognized the importance of preserving these forests and purchased much of the Muir Woods area in 1905.

Trail Map I Trail Photos

To ensure permanent protection, they donated 295 acres to the federal government; in 1908, President Theodore Roosevelt designated the area a National Monument.

At the request of William Kent the park was named for John Muir, an ardent conservationist, philosopher, scientist and author.

"This is the best tree-lover's monument that could be possibly found in all the forests of the world. You have done me great honor, and I am proud of it." - John Muir to William Kent. 

California coast redwoods (Sequoia sempervirens) are the world's tallest living organisms, and there are few better showcases than Muir Woods National Monument. The Main Loop Trail is a short and easy excursion for anyone, a wide, flat wood-plank trail lined by old growth redwoods.

The trail begins its interpretive portion section from the second bridge on the Main Loop. Be sure to purchase the interpretive brochure at the entrance station prior to embarking. Follow the numbered markers as each have their own story to tell about the ecology of Muir Woods.

Primitive plants line the trail, creating a lush green forest floor and include horsetail, ferns, moss and lichens. Redwood Creek, which follows the trail and flows through Muir Woods, provides a perennial water source for plants, animals, and a protected habitat for spawning Coho and Steelhead Salmon.

At .45 miles you'll reach the Hillside Trail junction. The Hillside Trail runs parallel to the Main Loop Trail but at a slightly higher elevation, providing an 'aerial' view of Muir Woods. Should you choose this spur, the Hillside Trail eventually returns you to Bridge #4 at the top of the Main Loop Trail.

Should you not take the Hillside Trail, continue along the Main Loop Trail and at .6 miles, you reach Cathedral Grove, a 'quiet area' where visitors are asked to remain silent. The coastal redwoods in Cathedral Grove are some of the biggest in Muir Woods and the trail remains easy through this section for the next .5 miles.

At the end of Cathedral Grove, you can either turn back and complete the loop via the Main Loop Trail, or you can cross bridge #4 and take the Hillside Trail (mentioned above) back to the main trail. Please note that the Hillside trail cannot accommodate wheelchairs.

Coastal Redwoods

Over 150 million years ago Redwood and Redwood-like trees covered most of the Northern Hemisphere. As the climate changed, redwoods thinned out and today there are only two species of redwoods in California: the coast redwood (Sequoia sempervirens), seen here in Muir Woods, and the Giant Sequoia (Sequoiadendron giganteum) found in Yosemite and Sequoia / Kings Canyon National Park.

While the giant sequoia grows in greater bulk, the coast redwood grows taller, reaching recorded heights of up to 379' (tree located in Redwood National Park). This makes them the tallest living organisms in the world.

The tallest coastal redwoods in Muir Woods are in the Bohemian and Cathedral Groves; the tallest tree in the park stands over 252' high with a maximum width of over 14'.

Redwoods can live to be 2000 years old. The average age of the coast redwoods in Muir Woods is between 600 and 800 years, with the oldest tree over coming in at over 1200 years. Redwoods grow best in moderate temperatures and need significant moisture to thrive. Part of the reason why redwoods thrive along the California coast is due to year round fog.

This perennial fog condenses on the leaves and needles of the trees, drips to the ground and provides redwoods with annual moisture, even during the dry season.

Redwoods are best known for their thick, spongy red bark. The bark itself can be from from 6 to 12 inches thick and insulates mature redwoods against fire damage. Redwoods get their color and name from the reddish-brown, bitter chemical tannin. Tannin makes the bark and wood resistant to fire and attack by fungi and insects.