Open Space Preserves

This collection of links contains useful information on open space preserves located in the County of Marin.

Alto Bowl

Small 37 acre preserve.

Bald Hill

This small preserve sits beside the Worn Springs Fire Road at the edge of lands.

Baltimore Canyon

193 acre preserve at the headwaters of Larkspur Creek.

Blithedale Summit

This preserve is the largest link (638 acres) in a chain of preserves.


This coastal preserve 1077 acres in size.

Bolinas Lagoon Advisory Council

To advise the Board of Supervisors, and other departments on the management and ecological restoration of Bolinas Lagoon.

Bothin Marsh

106 acre preserve incorporates a tidal wetland.

Camino Alto

Contains a variety of habitats including grasslands, bay/oak woodlands.

Cascade Canyon

Lush preserve, tucked into the hills above Fairfax, is one of the true gems of Marin.

Deer Island

No longer a true island, this preserve rises above the eastern edge of Novato.

French Ranch

The south-facing slope above the western end of the San Geronimo Valley.

Gary Giacomini

1500 acre property gives a sense of true wilderness.

Horse Hill

The sight of horses grazing on hillside has been a landmark for decades.

Ignacio Valley

The spectacular views and the sense of solitude make the climbing worthwhile.

Indian Tree

One of the best preserves to visit during a summer heat wave.

Indian Valley

Has variety of trails and roads in this preserve that offer loop hikes.

King Mountain

Home to amphibians like California Giant Salamanders and Ensatinas.

Little Mountain

See Western Tiger Swallowtail butterflies during spring and summer.

Loma Alta

Spectacular views of the entire Bay Area throughout.

Loma Verde

Forms a contiguous band of undisturbed open space.

Lucas Valley

Has much of the south-facing slope rising above what is now known as Lucas Valley.

Maurice Thorner Memorial

Hosts a single trail that carries hikers to the top of the San Geronimo Valley.

Measure A Community Oversight Committee

The purpose of the Measure A Community Oversight Committee is to review expenditures of Measure A funds on an annual basis to ensure they conform with the Measure A Expenditure Plan.

Mount Burdell

Along the way, visitors pass through lush grasslands.

Old Saint Hilary's

The only place to see the rare Tiburon jewelflower.

Pacheco Valle

A 519 acre preserve forms a contiguous band of undisturbed open space.

Ring Mountain

One of the most valuable pieces of real estate on the planet.

Roy's Redwoods

Overlooking the heart of the beautiful San Geronimo Valley.

Rush Creek

Perhaps the most popular asset of this 522 acre preserve.

San Pedro Mountain

Form an impressive backdrop to the Marin County Civic Center.

Santa Margarita Island

Remnant of a grand plan to create a subdivision resembling the city of Venice.

Santa Venetia Marsh

33 acre preserve features a small patch of salt marsh surrounded by a levee.

Terra Linda/Sleepy Hollow Divide

Large preserve protects the ridges that surround several small communities.

Tiburon Ridge

Small 15 acre preserve that is least used, but most visible among all MCOSD lands.

Verissimo Hills

A 115 acre preserve in western Novato protects a ridge.

White Hill

During spring, this landscape is quite picturesque.