Sources and Licenses
Every number on townzips.com comes from these files. Each was downloaded once, frozen with its date, and checked by its file hash before every build.
ZIP codes and post offices
- USPS ZIP Locale Detail, file of October 1, 2026, from the Postal Service's PostalPro site (postalpro.usps.com): every ZIP code, its type and its post office. The page carries no terms of use; as a U.S. government work we treat it as free to reuse (our reading, not a statement from USPS).
- GeoNames postal codes, US file seen October 19, 2026: the town name the mail uses for each ZIP code. Licensed under CC BY 4.0 by GeoNames.
- HUD-USPS ZIP Code Crosswalk Files, 2026 Q2, U.S. Department of Housing and Urban Development, Office of Policy Development and Research: the county of each ZIP code. This site is not endorsed or certified by HUD.
Maps, places and streets
- U.S. Census Bureau: ZIP Code Tabulation Areas (2020, cartographic boundary files 1:500,000), place and county subdivision boundaries (2024), the ZCTA relationship files (2020), the 2026 Gazetteer files, the American Community Survey 5-year estimates 2020 to 2024 (table B01003, town population) and TIGER/Line 2026 address range files (the street lookup). Source: U.S. Census Bureau. TIGER/Line is a registered trademark of the U.S. Census Bureau; these files are free to use with this acknowledgement.
- GeoNames gazetteer, US file modified October 20, 2026: the time zone of each town (CC BY 4.0, GeoNames).
City neighborhood names
- Houston: City of Houston Super Neighborhoods, Planning and Development Department (public domain), retrieved October 20, 2026.
- Chicago: City of Chicago, Boundaries: Neighborhoods (data.cityofchicago.org), retrieved October 21, 2026. This site provides applications using data that has been modified for use from its original source, www.cityofchicago.org, the official website of the City of Chicago. The City of Chicago makes no claims as to the content, accuracy, timeliness, or completeness of any of the data provided at this site. The data provided at this site is subject to change at any time. It is understood that the data provided at this site is being used at one's own risk.
- Philadelphia: Philadelphia Neighborhoods by Robert Cheetham (Azavea), from OpenDataPhilly, licensed CC BY 4.0, retrieved October 21, 2026.
- San Diego: City of San Diego community planning districts (data.sandiego.gov), retrieved October 21, 2026.
- Indianapolis: Indy Neighborhoods. Data courtesy of the City of Indianapolis and Marion County, Indiana; retrieved October 21, 2026.
- San Francisco: City and County of San Francisco, Analysis Neighborhoods (data.sfgov.org, Open Data Commons PDDL), retrieved October 21, 2026.
- Seattle: City of Seattle, Neighborhood Map Atlas (PDDL), retrieved October 21, 2026.
- Tampa: City of Tampa, Neighborhoods (CC0), retrieved October 21, 2026.
- Neighborhood names for Los Angeles: Data from Who's On First, current neighborhood records with outlines, retrieved October 21, 2026.
Neighborhood names are matched to ZIP areas by how much they overlap; a name means part of that neighborhood lies in the ZIP area. Other big cities group their ZIP codes by post office only.
Reusing our maps
Our ZIP code maps are drawn from the Census Bureau boundaries above. You may reuse a map, in print or online, if you credit it as "townzips.com; boundaries: U.S. Census Bureau" and link to the town page it comes from. For other uses, write to corrections@townzips.com.