ZIP code 57621 is officially located in the state of South dakota, primarily serving the city of Walker. It falls under the administrative jurisdiction of Corson County. When planning mail delivery, logistics routing, or demographic research, 57621 operates within the Central Time (CT) timezone and supports the 820 area codes.
According to the latest US Census Bureau and American Community Survey (ACS) datasets, the total population residing within the 57621 ZIP Code Tabulation Area is approximately 7,820. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $97,621.