Sonoma developmental center SPECIFIC PLAN

The Sonoma County Board of Supervisors adopted the Specific Plan on December 16, 2022! The board resolution and adopted Specific Plan are available on the Project Document page. 

The adopted Specific Plan, adoption resolution, and accompanying documents are posted on this website. 

The SDC is a nationally-recognized institution in the heart of Sonoma Valley. At 945 acres, the property includes a large historic campus, agricultural lands to the east, and vast ecological and open space resources. The SDC provided services to persons with developmental disabilities for over 120 years; it has a deep history in the valley and came to be recognized as a place of healing and community. The SDC was the County’s largest employer in its heyday. In 2018 the State of California officially closed the facility and relocated clients to smaller, community-based care facilities. The State of California owns the site forged a unique partnership with Sonoma County that allows the County, together with the community, to chart the future role of the SDC.

Adopted Specific Plan

Board of Supervisors Resolutions

Resolutions of the Board of Supervisors of the County of Sonoma, State of California, certifying the Environmental Impact Report for the SDC Specific Plan Project.


Specific Plan vision

The former Sonoma Developmental Center (SDC) is reinvigorated as a vibrant and sustainable community in the heart of Sonoma Valley. A mixed-use, pedestrian-oriented core provides a diverse array of housing choices, and serves as a magnet of innovation, research, education, and visitation. The surrounding open spaces flourish as natural habitats and as agricultural and recreational land linked to regional parks and open space systems. Development builds on the site’s rich historic legacy while meeting contemporary needs, emphasizing resiliency and sustainable building practices. Civic uses, community gathering places, and events attract visitors from Glen Ellen, Eldridge, and the broader Sonoma region, making the center a hub of community life in Sonoma Valley.

The former SDC site has emerged as a culturally and ecologically vibrant and resilient community. A core 180-acre developed area is surrounded by a vast protected open space of oak woodlands, native grasslands, wetlands, forests, creeks, and lakes that provide habitats and wildlife movement corridors; agricultural land; and recreational open space integrated with the surrounding park systems.

The developed core area comprises a complementary mix of housing, commercial, and institutional uses. The SDC site is financially independent and supporting infrastructure is up to date and well maintained. A variety of housing—including affordable, workforce, mid-income, and market-rate housing; senior housing; housing for people with developmental disabilities; and in new and adaptively re-used buildings—will foster a diverse and inclusive community. New development complements the adjacent communities of Glen Ellen and Eldridge. Residents enjoy pedestrian access to essential services and parks, and seamless connections to surrounding open spaces. Employment opportunities reflect the site’s legacy of care and emphasize innovation, research, education, environment, and ecology, together with supporting commercial and visitor-serving uses. Sonoma Valley’s former largest employment hub is reinvigorated as a regional model for sustainable development.

The reinvigorated community builds upon the site’s rich historic legacy while embracing the future. Key historic resources—including the Sonoma House and the Main Building—have been repurposed for contemporary uses, and elements of the historic landscape preserved. Site design patterns—streets layout, building/street relationship, streetscape character—maintain east-west views to the Sonoma and Mayacamas mountains and foster a harmonious sense of place. Contemporary buildings are intermixed with repurposed historic structures, creating a rich and visually cohesive development fabric.

A comprehensive network of pedestrian and bicycle paths connects residents to local and regional destinations, and to transit. Well-designed bus stops, crosswalks, and protected bike lanes create an inviting sense of safety for those of all ages and abilities and provide better walking and biking access to Glen Ellen and Eldridge, and to the regional bicycle network.

New land uses contribute positively to the site’s financial feasibility, enabling efficient and sustainable construction of necessary infrastructure. Water is conserved and reused, and safety and fire protection built into the landscape, with defensible design, new fire-resistant buildings, and well-planned evacuation routes. Reuse of historic buildings has saved resources needed for new construction, and building designs reflect sustainable practices and wildfire resiliency. The surrounding open spaces, preserved in perpetuity, are home to countless local species that use SDC’s habitat corridors. Sightings of wildlife throughout the site and along Sonoma Creek enrich life for residents.

The SDC site has become a multilingual gathering place for the Sonoma Valley, with public spaces for lingering and enjoying a cup of coffee or a meal; community amenities, cultural spaces, and events; playfields and recreational spaces for soccer games or a game of fetch; and seamless connections to the extensive trail networks of the SDC property, Jack London State Park, Sonoma Valley Regional Park, and the surrounding mountains.