County lookup by ZIP code
Find a ZIP code's reference county and FIPS code.
A ZIP can cross county lines.
Use it in your app
GET /postal/33139?country=US
The reference county is returned as district and district_name when known. This page is one /postal call from your browser. Same endpoint on every plan, one pooled request per lookup.
ZIP code APIDistrict APITimezone by ZIPCounty at my location
QUESTIONS
- What is a FIPS code?
- The 5-digit federal code for a county. The first two digits are the state, the rest the county. Census data, health data, and most government files key on it.
- Louisiana and Alaska?
- Parishes and boroughs sit at the same grain and come back the same way.
- Can a ZIP cross county lines?
- Some do. This is one county for the ZIP; use coordinates to check a specific location.
- Can I do this from code?
- Yes. GET /postal/{code}?country=US returns the reference county as district and district_name where known. One pooled request.