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This layer originated from ZCTAs and has been modified in places by Grant County GIS staff based on input from local US Postal Service staff and landowners.
ZIP Code Tabulation Areas (ZCTAs™) are a statistical geographic entity produced by the U.S. Census Bureau for tabulating summary statistics from the 2010 Census, first developed for Census 2000. This entity was developed to overcome the difficulties in precisely defining the land area covered by each ZIP Code™, which is necessary in order to accurately tabulate census data for that area.
ZCTAs are generalized area representations of U.S. Postal Service (USPS) ZIP Code service areas. They represent the most frequently occurring five-digit ZIP Code found in a given area. Simply put, each ZCTA is built by aggregating 2010 Census blocks, whose addresses use a given ZIP Code. Each resulting ZCTA is then assigned the most frequently occurring ZIP Code as its ZCTA code. For more information, please refer to the ZCTA Frequently Asked Questions (FAQ).