ZIP Codes by State, County & City
Look up a city and state with Zippopotam, or sample OSM address postcodes in areas matching a county name. Results may be incomplete; county matches are not state-filtered.
By Aryan Khan, Founder & Editor · Updated October 2026
City and county lookup modes use different sources; a state-only list is not available.
How to use ZIP Codes by State, County & City
Choose a city or county lookup:
Search a city and state through Zippopotam, or collect postcodes from up to 800 mapped OSM objects inside areas matching a county name. County matching is not state-filtered; results may be incomplete or combine places with the same name.
- 1Choose “By city” or “By county”.
- 2Enter the state and city, or the county name.
- 3Press “Find ZIP codes”.
What people use ZIP Codes by State, County & City for
1. Territory and franchise lists
Use returned codes as a preliminary territory reference, then check names and coverage against an authoritative current source.
2. Mailing and outreach targeting
Explore a city’s provider-listed codes before preparing a mailing list; this page does not offer a state-wide export.
3. Data validation
Compare reported postcodes with other sources. This sample is not a definitive address-validation service.
4. Service-area definitions
Inspect codes associated with a city or mapped addresses in matching county areas. For a separate geographic view, see the ZIP Code Boundary Viewer where edges matter.
Worked examples
A city query and a county-name query use different datasets and do not necessarily return the same codes or boundaries.
A code can be recorded on addresses in more than one area. Absence from the capped OSM sample does not prove that it is not used there.
Available lookups
Choose the source and scope that match your question.
| Slice | Answers | Watch out |
|---|---|---|
| City and state | Zippopotam city lookup | Provider coverage can be incomplete |
| County name | OSM address postcode tags | No state filter; up to 800 objects and 300 displayed codes |
| State only | Not available | Use a suitable postal data source |
ZIP codes are postal delivery constructs. These results are not official boundary or mailing validation.
Data & methodology
City: Zippopotam.us place lookup. County: Overpass area query collecting addr:postcode values inside the boundary, deduplicated.
For source details, licences and model limitations, see Data Sources and Methodology.
Editorial guidance: MapBench explains the method and limitations so the tool can be used as a transparent reference, not as a black-box answer. For legal boundaries, safety-critical routing, surveying, engineering, regulated decisions or official statistics, verify the result with the responsible authority or a qualified professional.
Category: Places & Population. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
Method, assumptions & limits
- This tool’s method
- City: Zippopotam.us place lookup. County: Overpass area query collecting addr:postcode values inside the boundary, deduplicated.
- Before relying on the answer
- Check whether the result counts dataset points, administrative areas or an estimated population footprint. Record the source vintage when provided.
- What the result cannot establish
- Settlement points and area totals do not represent a complete count of residents inside an arbitrary shape. Survey estimates also carry uncertainty.
Coverage: US focused. Search, basemap and external data requests may use third-party services; browser-based does not mean every operation is offline. Read the source and licence notes, calculation methodology and privacy policy. If a result looks inconsistent, report a correction with the inputs and mode used.
Frequently asked questions
Clear answers about the calculation, accuracy and appropriate use.
Are county results the official USPS list?
No. County mode samples OSM objects by county name without filtering state; city mode uses Zippopotam. Neither is a guaranteed complete or official list.
Why does state-only not appear?
A whole state can hold thousands of ZIPs; the useful questions are city and county, so those are the two modes offered.
Is this an official census result?
Only when a page explicitly uses and labels an official census dataset. Many tools are estimates or curated dataset summaries and explain that limitation on the page.
Why might population figures differ from another website?
Population values can use different census years, boundaries, estimates and definitions of city or metro area.
Can I use the result for market planning?
Yes as an exploratory reference, but validate commercial decisions with current official or specialist demographic data.
Why is a ZIP on two counties' lists?
A code may be present on addresses in more than one matched area; a result alone does not establish its delivery boundary. County names are not state-filtered.
Postal city versus real city?
USPS assigns each ZIP a preferred city name that can differ from the municipality the address sits in. The city slice follows postal naming and says so; civic truth lives with the boundary tools.
Are unique ZIPs (single buildings) included?
Codes serving one facility exist in the postal file; list tools vary in carrying them. For mailing work their absence rarely matters; for completeness claims, the note on the list governs.
How often do ZIP lists change?
USPS creates, splits and retires codes continuously as delivery grows. Any frozen list is a snapshot — for production mail, current CASS-grade data is the standard.
Can I get the list as a file?
The current workspace displays a result list; it does not offer a dedicated file export.
Canadian or UK equivalents?
Different systems, different tools: Canada's FSAs and UK postcode districts live in the Location family's postcode tools, sliced their own ways.
What about ZIP+4?
The +4 refines delivery within a ZIP and multiplies the list a thousandfold — reference lists live at the 5-digit level, where geography still means something.
Related tools and resources
Plot them: the ZIP Code Map; inside a circle: ZIP Codes Within Radius; Australia's system: Australia Postcodes by State & Suburb.
More free tools
Sources, methodology & editorial trust
- ✓ Browser-first processing where supported
- ✓ External sources are documented
- ✓ No account required for public tools
- ✓ Review data sources
Calculations are documented with their assumptions, limitations and source context rather than presented as unexplained answers.
Reviewed and maintained by Aryan Khan, Founder & Editor of MapBench.
Part of our boundaries & lookups hub
ZIP Codes by State, County & City sits in the boundaries & lookups cluster, alongside 39 other tools that answer neighbouring questions with different methods or datasets.
You may also need
When this answer is only part of the job, these clusters cover the next step.
Read the guide behind this tool
What County Am I In? How County Lookup Actually Works — County lines are legal boundaries, not vibes. How map tools resolve a point to a county — and why borders, unincorporated areas, and bad GPS fix create surprises.