According to the United States Census Bureau, the population of Santa Rosa was approximately 177,000 as of 2021. Situated in the heart of California's wine country, Santa Rosa spans over 43 square miles and has a population density of 4,117 people per square mile. The median age of residents in Santa Rosa is 39.6 years, with males having a median age of 38.2 years and females having a median age of 41 years.