ZIP code 78631 is officially located in the state of Texas, primarily serving the city of Harper. It falls under the administrative jurisdiction of Gillespie County. When planning mail delivery, logistics routing, or demographic research, 78631 operates within the Central Time (CT) 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 78631 ZIP Code Tabulation Area is approximately 29,843. Understanding local economics is critical for market analysis; the median household income in this postal area sits at $67,631.