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Sonoma Developmental Center

Heart of Sonoma Valley and the Core of the Valley’s Wildlife Corridor

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At almost 1,000 acres, the Sonoma Developmental Center (SDC) property is the largest and most significant unprotected land in the Sonoma Valley. In addition to providing services for developmentally disabled individuals, this property is situated at the heart of the Sonoma Valley Wildlife Corridor, a crucial passage for wildlife that extends over 5 miles from Sonoma Mountain to the Mayacamas Mountains and is at risk of being developed. 

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What is at Risk:

SDC WildlifeThe loss of the SDC facilities and open space to incompatible development would have far-reaching consequences, affecting hundreds of patients and their families, over 1,000 employees, support services in the local community, critical habitat for fish and wildlife, and the potential for recreation and public access.

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The Coalition is working to:

  • Retain the Sonoma Developmental Center services on the property,
    and explore other complementary and appropriate uses within the
    footprint of the facilities.
  • Advocate for the permanent protection of the open land on the
    SDC property and the essential services it provides, such as habitat
    and movement corridors for wildlife, clean and ample drinking
    water, a place of beauty for us to enjoy, and carbon sequestration,
    among many others.
  • Expand public access and recreation opportunities that are compatible
    with the protection of the property’s conservation values,
    including the development of new trails and connections to existing
    trails on Sonoma Mountain, and potentially across Sonoma Valley to
    the complex of protected lands within the Mayacamas Mountains.

Sustainable SDC Services

SDC State Facility Property The property is home to a State facility that has served developmentally disabled people for more than 120 years and occupies approximately 20% of the property. The Parent Hospital Association (PHA) was established in the 1950s by parents, family members and friends of patients living at SDC to improve conditions, and advocate on behalf of all people who need the specialized care that this Center provides. The campus provides clients with access to the outdoors in a safe and beautiful setting. Also, the SDC is the largest employer in the Valley with a workforce of 1,200; it is an integral part of the Sonoma Valley community and its economic vitality.

Diverse Habitat and Connected Corridors for Wildlife

SDC Diverse Habitat

The SDC property contains oak woodlands, Douglas fir forests, redwoods, grasslands, lakes, wetlands, and streams. Deer, mountain lion, coyote, and bobcat, and rare species such as steelhead trout, northern spotted owl, and California red-legged frog live here. Sonoma Creek, which runs through SDC for about three quarters of a mile, is one of the County’s most significant streams for steelhead. In addition, the property provides significant water resources for the surrounding community.

Permanent protection of the undeveloped portions of the SDC will link over 9,000 acres of protected land, home to many rare native plants and animals. The property is recognized as a regionally significant linkage connecting the Marin coast to the interior coast ranges of California.

SDC is the last large undeveloped property in Sonoma Valley, and the loss of its exceptional habitat to incompatible development will likely have devastating effects on wildlife movement across the Valley.


SDC is the only single property in Sonoma Valley that is poised to recreationally connect Sonoma Valley Regional Park to Jack London State Park, with its network of publicly accessible lands, and bikeways and transit options that link to Sonoma and Santa Rosa.

There is substantial existing public investment in the land; over 12 miles of trails, equestrian, group and camp facilities, and scenic lakes are enjoyed every day by the public. Multiple-use trails on SDC lands link to a network of trails that connect to Jack London State Park and Sonoma Mountain. If the SDC were to be closed and the property sold, the existing public access and expanded new recreational opportunities would be jeopardized.

SDC Property MapThe gentle topography supports accessible trails that appeal to all segments of the population. This property can provide access to nature and to healthy lifestyles in a way that no other Sonoma Valley facility can.

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Contact Information

Business Hours
Monday – Friday
8:00 AM – 5:00 PM
Contact us by Phone
Board of Supervisors
575 Administration Drive
Room 100 A
Santa Rosa, CA 95403
38.464626, -122.725441

A Coalition of Organizations Urges your Support for the Sonoma Development Center

Audubon Canyon Ranch

Parent Hospital Association

Sonoma County Agricultural Preservation and Open Space District

Sonoma County Regional Parks Department

Sonoma Ecology Center

Sonoma Land Trust

Sonoma Mountain Preservation

Valley of the Moon

Natural History Association