ZIP code 21758 is officially located in the state of Maryland, primarily serving the city of Knoxville. It falls under the administrative jurisdiction of Frederick County. When planning mail delivery, logistics routing, or demographic research, 21758 operates within the Eastern Time (ET) timezone and supports the 658 area codes.
According to the latest US Census Bureau and American Community Survey (ACS) datasets, the total population residing within the 21758 ZIP Code Tabulation Area is approximately 15,358. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $126,758.