Data sources

US ZIP Code Map compiles a commercial ZIP directory with public Census and IRS tables. We do not republish the paid extract as an open download, and Dataset markup on ZIP pages does not claim an open license on that file.

U.S. Census Bureau

• American Community Survey (ACS) 2023 five-year estimates (period 2019–2023) for ZCTA, place (summary level 160), county (050), and state (040) population (B01003), households (B11001), median household income (B19013), and median home value (B25077).
• TIGER ZIP Code Tabulation Area (ZCTA) boundaries drawn on the map. These approximate USPS ZIP codes; they are not delivery routes.

Official ACS documentation: census.gov/programs-surveys/acs. Table-based summary files: www2.census.gov ACS 2023 5-year table-based SF.

Internal Revenue Service

IRS Statistics of Income (SOI) ZIP Code data supply historical population and household counts and the IRS column on each ZIP history table. Official SOI ZIP files: IRS SOI ZIP Code data.

Commercial ZIP directory

City, county, type (standard / PO Box / unique / military), area codes, overlap percentages, and the vendor population_count come from a purchased ZIP extract. That file is licensed to this site. It is not Creative Commons or public-domain data. We do not commit those CSVs to git.

Maps

Basemap tiles and optional address geocoding use Google Maps JavaScript, Places, and Geocoding APIs. Census ZCTA outlines are our overlay, not Google’s ZIP product.

How we cite them

KPI footnotes name the dataset, period, vintage, and geography (ZCTA, place GEOID, or county GEOID). Census city and county headlines are ACS for that GEOID. USPS-only mailing cities with no place GEOID are postal city pages with a labeled ZIP-sum — see methodology. Start with 77007, Houston, or the about page.