ZIP code 99121 is officially located in the state of Washington, primarily serving the city of Danville. It falls under the administrative jurisdiction of Ferry County. When planning mail delivery, logistics routing, or demographic research, 99121 operates within the Pacific Time (PT) timezone and supports the 672 area codes.
According to the latest US Census Bureau and American Community Survey (ACS) datasets, the total population residing within the 99121 ZIP Code Tabulation Area is approximately 44,772. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $97,121.