Every answer on this site comes from public data. Here is what we use for each field, how current it is, and where it can be wrong.
Location lookups
When you share your location, type an address or tap the map, we send that point once to the U.S. Census Bureau Geocoder, which reports the boundaries the point falls inside. We don’t store the point.
- ZIP code area: 2020 Census ZIP Code Tabulation Areas (ZCTAs).
- County, state, city and census designated places: current Census TIGER boundaries, updated each year through the Boundary and Annexation Survey.
- Congressional districts: districts for the 120th Congress, elected in November 2026. States that redraw their maps mid-decade update these through the Census.
- State legislative districts: 2026 upper and lower chamber districts.
- Addresses: matched against Census address ranges. New streets and rural routes can fail to match; try the nearest cross street or use the map.
ZIP code data
- ZIP to county and city shares: Census 2020 ZCTA-to-county and ZCTA-to-place relationship files. Shares are by land area.
- ZIP centers and land area: Census 2025 Gazetteer files.
- Mailing city names: GeoNames postal code data, licensed under CC BY 4.0. This also covers PO Box and single-address ZIPs that have no Census area.
Time zones
Time zones are looked up from coordinates with the open-source tz-lookup data, built from time zone boundary maps. The current offset and daylight saving status come from your browser’s time zone database.
Your approximate location
Before you share anything, the page shows a guess based on your internet connection, provided by our host, Cloudflare. It’s labeled “approximate” because IP-based locations can be a city or a state away.
Maps
Base maps by OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors. Boundary outlines come from Census TIGERweb.
What this site is not
- Not USPS. ZIP code areas are Census approximations. USPS’s own boundary data is a paid product we don’t use. For the ZIP or ZIP+4 of a mailing address, use the USPS ZIP Code lookup.
- Not a legal or survey record. For property lines, tax jurisdiction or annexation status, the county appraisal district or city planning office has the official answer.
ZIP Code™ and ZIP+4® are trademarks of the United States Postal Service. We are not affiliated with USPS or the Census Bureau.
Spotted a wrong answer? Email contact@mylocationinfo.com with the place (not your home address, a nearby intersection is fine) and what you expected.