ZIP code 21664 is officially located in the state of Maryland, primarily serving the city of Secretary. It falls under the administrative jurisdiction of Dorchester County. When planning mail delivery, logistics routing, or demographic research, 21664 operates within the Eastern Time (ET) timezone and supports the 443 area codes.
According to the latest US Census Bureau and American Community Survey (ACS) datasets, the total population residing within the 21664 ZIP Code Tabulation Area is approximately 17,243. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $128,664.