1.9 mile out and back hike in a small preserve with grassland and rolling
Distance, category, and difficulty:
This nearly 2 mile out and back hike is easy. The preserve's
lowest elevation is about 300 feet. Highest elevation is about 520 feet.
Hiking is easy in this small preserve.
More sun than shade.
Nice any time.
From US 101 in Marin County, exit San Anselmo/Sir Francis Drake. Drive
about 11 miles west on Sir Francis Drake, and turn right onto Nicasio
Valley Road. Drive about 0.4 mile, then park on the side of the road near
the open space gate.
Get driving or public transit directions from Transit and Trails:
GPS coordinates* for trailhead:
(* based on Google
Earth data, shown as degrees, minutes, seconds)
Gas, food, and lodging:
Gas, pay phone, stores and restaurants back east in Fairfax. For breakfast
before, or lunch after a hike, I recommend Two Bird Cafe on San Geronimo
Valley Drive in San Geronimo (visible from Sir Francis Drake). No camping.
No parking or entrance fees. Substantial roadside parking. No maps, drinking
water, or designated handicapped parking. Pit toilets inside Roy's Redwoods
Preserve. There is no direct public transportation to the preserve, but
Golden Gate Transit bus #23 services San Geronimo Valley Drive. From there
you could walk about 0.5 mile to the trailhead
The preserve's single trail is closed to cyclists. Dogs are permitted.
The Official Story:
Maurice Thorner page.
Marin County Department of Parks, Open Space, and Cultural Services: (415)
Use AAA's San Francisco Bay Region map to get there
Download the pdf
map from MCOSD
Don and Kay Martin's Hiking Marin has a useful map of the
preserve and the surrounding area (order
this book from Amazon.com).
Barry Spitz's Open Spaces (order
this book from Amazon.com)
Thorner Open Space Preserve in a nutshell -- a printable, text-only
guide to the featured hike.
View photos from this
Go to Bay Area Hiker Home page
Thorner Memorial is a tiny and little-known open space
preserve near San Geronimo in Marin County. For years, the only access
was at the end of Lagunitas School Road, and the single trail ended at
a hilltop overlooking a golf course and Roy's Redwoods. In September 2000,
MCOSD completed an extension connecting Maurice Thorner Memorial with
Roy's Redwoods (via the golf course bridge). This permits hikers to explore
the two small preserves in once visit.
Summer and autumn are best spent elsewhere.
There is little shade on the ridge, and Thorner Memorial lacks significant
foliage trees. The grassland retains some late spring wildflowers, and
you might enjoy the preserve in late winter, when the ridge is swathed
in fresh green grass.
Although Thorner Memorial has its own trailhead
at the end of Lagunitas School
Road, parking is limited there and restricted during school hours. Roy's
Redwoods Open Space Preserve provides easier access, and since Thorner
is small, you probably won't mind adding a little extra mileage to your
hike. Start at the open space gate on Nicasio Valley Road. Turn
right (looks like the path ends at the portable toilets, but it doesn't),
and follow the signposts for horse traffic. The narrow path, open
to hikers and equestrians only, goes right at the toilets, then becomes
indistinct in a pretty redwood grove. Stay to the right of the creekbed
(although there's another trail on the other side), and look for a path
heading south out of the woods. Blackberry brambles crowd the trail. The
trail crosses a bridge; turn right on the far side. Ascending
easily, Loop Trail soon leaves the woods behind and enters grassland. Nicasio Valley Road is visible as the trail parallels the road. After
a few gentle dips, the trail reaches an unsigned junction at 0.26 mile.
Bear right and cross the golf course bridge. At the end of the
bridge, Thorner Ridge Trail begins at an unsigned junction. Turn left.
Thorner Ridge Trail, open to hikers and
equestrians, ascends gently. Coyote brush is common, as are invasive broom
plants. You might see Ithuriel's spear, yellow mariposa lily, and clarkia
in late spring. Spiky teasel plants line the narrow path. There are nice
views past the golf course back to Roy's Redwoods. Thorner Ridge Trail
crosses through a patch of stunted blackberry and soon after reaches the
ridge line, joining the preserve's previously existing trail. Bear
Pure grassland is interrupted by occasional
coyote brush shrubs as the trail runs along the ridge at an easy grade.
The lookout at Samuel P. Taylor is visible to the west, as is the ridgeline
in Giacomini Open Space Preserve, to the south. A look back to the east
reveals White's Hill and Loma Alta. Thorner Ridge Trail approaches and
then enters a compact forest of madrone, coast live oak, big-leaf maple,
California bay, nutmeg, and hazelnut. Beware of poison oak. Switchbacks
wind downhill, and as the trail reemerges into grassland, the end of the
preserve is in sight (you may want to turn around here). The trail descends
on broad switchbacks, and ends, at 0.97 mile, near a school. Retrace
your steps back to the trailhead.
Total distance: 1.94 miles
Last hiked: Wednesday, June 6, 2001