Demographics and Social Characteristics

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Read Next in Sonoma County Summary Measures of Health 2015-2017:
Average Life Expectancy

The demographic characteristics of a population, such as sex, age, and race/ethnicity, strongly influence the disease burden within a community.  Examining the demographics of the Sonoma County population provides context to the average life expectancy and premature mortality data explored in this report.

In 2016, Sonoma County had an estimated 503,000 residents. The median age in Sonoma County was 42.1 years. Twenty-five percent, or about 127,000 residents, were between the ages of 25 and 44 years and another 28% were between the ages of 45 and 64. About one in five residents (92,000 or 18%) was age 65 and older.

Figure 1. Population distribution by age category and sex, Sonoma County 2016

Source: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, Bridged-Race Population Estimates 2016; US Census Bureau, ACS 1 Year Est. 2016, Table: B01001

There are many different racial and ethnic groups residing in Sonoma County; however, denominator data available for this analysis were limited to the five major racial/ethnic groups presented in Table 1. In 2016, the majority of Sonoma County residents (66%) were white, non-Hispanic. More than one in four residents (27%) were Hispanic/Latino. About 5% of the population were Asian/Pacific Islander, non-Hispanic, 2% were African American/Black, non-Hispanic, and less than 1% were American Indian/Alaska Native. The median age of White, non-Hispanics was 50.8 years, older than other racial/ethnic groups. Hispanic/Latino residents had the youngest median age (28.8 years). 

Source: U.S. Department of Health and Human Service, Centers for disease Control and Prevention, National Center for Health Statistics, Bridged-Race Population Estimates 2016; US Census Bureau, ACS 1 Year Est. 2016, Table: B01002B-I

Geographical areas (defined by zip codes) were aggregated for more stable and thus more meaningful analyses of data. Santa Rosa had the largest population (43.2%) of these aggregated zip codes, followed by Petaluma (14.7%). The smallest proportions of the population were in Healdsburg (3.5%), Russian River Area (2.8%), and Cloverdale/Geyserville (2.5%) (Table 2). 

Source: US Census Bureau, American Community Servey, 5 Year Estimates by Zip Code Tabulation Areas (ZCTA), 2013-2017

Social and economic characteristics also influence the health or disease burden of a community. Social determinants of health are conditions in the environments in which people live, learn, work, and play, that affect a wide range of health, functioning, and quality-of-life outcomes.¹  While many complex factors contribute to individual and community health, understanding some of these upstream measures, such as poverty and educational attainment, can help give context to the outcomes presented in this report.  Table 3 describes poverty and educational attainment in the county.

^ Of both Hispanic and non-Hispanic ethnicity
* Data for Pacific Islanders unavailable due to small numbers
- Data unavailable due to small numbers
Source: US Census Bureau, PUMS, 2016; American Community Survey, 1 Year Estimates, 2016 and ZTCA, 5Year Estimates 2013-2017 Tables S1701, and S1501, C1501B-H

In general, higher income and social status are linked to better health and longer life expectancy.² Sonoma County is a relatively affluent county. In 2016, about 59% of the population had incomes 300% or more than the Federal Poverty Level (FPL) – or about $73,000 per year for a family of four. Poverty in the county varied significantly by race/ethnicity and geography of residence. Hispanic/Latino and African American/Black residence were less likely than white, non-Hispanic and Asian residents to have incomes greater than or equal to 300% FPL (Table 3). Regionally, residents of the Russian River area, Rohnert Park, Santa Rosa, and Cloverdale and Geyserville were less likely to have incomes greater than or equal to 300% FPL than residents of Sonoma Valley, Sebastopol – West County, Healdsburg, Petaluma, and Windsor.

Educational attainment is also an important predictor of health with lower education levels linked to poorer health and a reduction in life expectancy.³ In 2016, about 88% of Sonoma County residents 25 years and older had a high school degree (or equivalent) or higher. Educational attainment differed by race/ethnicity and geography. White, non-Hispanic, Asian, and African American/Black residents age 25 years and older were more likely than American Indian/Alaska Native and Hispanic/Latino residents to have a high school degree (or equivalent) or higher. Geographically, Sebastopol-West County and the Russian River area had the highest proportion of residents 25 years and older with a high school degree (or equivalent) or higher. Santa Rosa, Windsor, and Cloverdale and Geyserville had the lowest proportion of residents with a high school degree (or equivalent) or higher.

Map 1. Sonoma County geographic analysis areas, 2016

For analysis purposes, Sonoma County was divided into nine major areas by aggregating zip codes. These areas include the following zip codes (Map 1).

See our interactive map or navigate to summary tables for each geographic area below.