ZIP code 21555 is officially located in the state of Maryland, primarily serving the city of Oldtown. It falls under the administrative jurisdiction of Allegany County. When planning mail delivery, logistics routing, or demographic research, 21555 operates within the Eastern Time (ET) timezone and supports the 796 area codes.
According to the latest US Census Bureau and American Community Survey (ACS) datasets, the total population residing within the 21555 ZIP Code Tabulation Area is approximately 11,996. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $75,555.