Sonoma County is the northernmost and physically the largest of the nine Bay Area counties. It has the largest undeveloped acreage in the Bay Area. Urban development is concentrated in the southern half of Sonoma along the Highway 101 corridor in the cities of Petaluma, Cotati, Rohnert Park, Santa Rosa, and Windsor. More than 65 percent of the county's population lives in these five cities. With a current population of over 140,000, Santa Rosa is the largest city between San Francisco and Eugene, Oregon, and its sphere of influence encompasses an area of nearly 50 square miles.

Between 2000 and 2030, the county will add about 40,740 households and over 107,100 residents. Nearly half (48 percent) of the households will be within the Santa Rosa area. In 2030, Sonoma County will constitute a smaller share of the region's population than it did in 2000.

Development Pattern

With virtually all cities in the county having an adopted urban growth boundary, most future development in Sonoma County is planned to be within city boundaries. However, according to a survey of local planning departments in Sonoma County, average residential densities in the county are declining and, during the past decade, Sonoma County urbanized more land for residential uses-11,000 acres-and more land overall-13,000 acres-than any other Bay Area county.

Sonoma County has also been attracting jobs at a furious pace, a trend that is expected to continue through 2020. In the next two decades, ABAG forecasts that job growth will increase almost 50 percent, while the number of housing units will grow at just half that rate. The result will be an employed residents-to-jobs ratio that is moving toward 1.0

Projected Growth in Sonoma County

Since the adoption of policy-based projections, Sonoma's population forecast is based on a conceptual growth pattern that may be different from existing local general plans and zoning. It is assumed that a new rail line will be developed to extend along the old Northwestern Pacific railroad right-of-way, from Cloverdale in northern Sonoma County to Larkspur in Marin County. This would create a variety of opportunities, at relatively low densities, for mixed-use developments and employment centers in Sonoma County.

The anticipated mix of household and employment growth in Sonoma County will create vital economic opportunities for the County's residents.

This growth concept promotes the preservation of the County's historic rural and agricultural character by encouraging increased housing densities in existing residential areas throughout the county.