Silverdale is an unincorporated community in Kitsap County, Washington, in the United States. Despite many failed attempts at incorporation, Silverdale has not become a city. The population was 20,733 at the 2020 census. For statistical purposes, the United States Census Bureau has defined Silverdale as a census-designated place. Silverdale ranks 158th among 522 areas in Washington for which per capita income data is collected.