How this data is sourced and computed
Every number on this site resolves to a named public dataset. Where a fact is not in one of them, the page says so and leaves the space blank rather than filling it with an estimate. Data last refreshed .
- Area codes
- 379
- ZIP codes
- 40,977
- Places
- 29,540
- County-equivalents
- 3,144
- Country records
- 248
Scope every record the platform ships. Source LocalCallingGuide NPA list (2026-07 NPA list), GeoNames US postal codes (2026-07 postal dump), Census 2024 county Gazetteer (2024 Gazetteer) and datasets/country-codes (E.164 + ISO 3166) (ITU-T E.164 + ISO 3166, 2026-07 release). Updated . Counts are the length of the generated datasets, not a stated total from any single source.
Sources in use
| Source | Vintage | Licence | Refreshed |
|---|---|---|---|
| Census 2024 county Gazetteer | 2024 Gazetteer | Public domain (US Gov) | |
| Census 2024 place Gazetteer | 2024 Gazetteer | Public domain (US Gov) | |
| Census Population Estimates (sub-est 2024) | 2024 population estimates | Public domain (US Gov) | |
| datasets/country-codes (E.164 + ISO 3166) | ITU-T E.164 + ISO 3166, 2026-07 release | Public domain (PDDL) | |
| geoinfo-dataset (full_dataset) ZIP→NPA | 2018 snapshot | MIT | |
| GeoNames US postal codes | 2026-07 postal dump | CC BY 4.0 (attribution required) | |
| LocalCallingGuide NPA list | 2026-07 NPA list | Public numbering facts (LERG/NANPA-derived summary only) | |
| libphonenumber PhoneNumberMetadata (Google) | libphonenumber master, 2026-08 snapshot | Apache-2.0 | |
| Wikipedia NANP table (in-service dates) | 2026-07 revision | Facts (not copyrightable); structure CC BY-SA |
County-equivalents
Not every state has counties. Connecticut abolished county government and the Census now uses planning regions as its county-equivalents; Louisiana has parishes; Alaska has boroughs and census areas; Virginia, Maryland, Missouri and Nevada have independent cities that sit outside any county. Pages here name whichever applies.
County-equivalent identity resolves by FIPS code against the Census Gazetteer, not by matching names. Name matching would carry through the postal dataset's suffix-less spellings and, in Connecticut, its pre-2022 county names. Twelve ZIP records still reference jurisdictions that have since been dissolved; those keep their original name with no suffix added.
Matching ZIP codes to area codes
ZIP codes and area codes are independent systems — one is postal, the other is telephone numbering — so the relationship between them has to be computed. It is built from real ZIP-to-NPA exchange data, then expanded with the authoritative overlay complexes, so a code that overlays another inherits the geography it genuinely shares.
Where a ZIP is not covered by that source, the match falls back to other ZIPs in the same city, then the same county. Every place records which method produced its codes, and pages say "associated with" rather than "serving" when the match was inferred.
What we deliberately leave blank
These sources would improve the site and are not integrated. Each is licensed, access-gated or proprietary. Nothing is synthesized to fill the gap they leave.
| Would provide | Why it is not here |
|---|---|
| a real state total instead of a sum of matched-place populations (state pages currently omit a total on purpose) | input file not provided; do not present the place-population sum as an official total |
| accurate multi-county ZIP relationships with residential/business ratios | requires manual, terms-gated download; single-county GeoNames label used meanwhile |
| real prefix counts and verified split history | no clean per-prefix source integrated; prefix count and split history both stay explicitly unknown |
| true ZCTA boundary maps (labelled as ZCTA, not USPS delivery areas) | geometry not committed; honest point-distribution maps ship meanwhile (§6.1) |
| verified ZIP delivery type | no clean-rights source exists; Zip.type stays "unknown" rather than fabricate a "standard" |
Limits
- Coordinates are record reference points, not USPS ZIP boundaries or ZCTA polygons. Any distance is centroid to centroid.
- Nothing here is USPS or carrier validation. It is reference data.
- Population is a Census estimate for the place, with its own vintage, and is absent for places the estimate does not cover.
- Data generated .