Santa Rosa's 2020 population is now estimated at 432,221. In 1950, the population of Santa Rosa was 17,539. Santa Rosa has grown by 79,695 since 2015, which represents a 4.16% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Santa Rosa, which typically includes Santa Rosa's population in addition to adjacent suburban areas.