Public ArcGIS MapServer endpoint for Fairfax County parcel data. URL, supported fields, and a working sample query — copy it, or open it directly in the UrbanKit parcel lookup tool.
https://www.fairfaxcounty.gov/mercator/rest/services/OpenData/OpenData_A9/MapServer/0/query?where=PIN+LIKE+'0304%'&outFields=PIN,PARCEL_TYPE&returnGeometry=false&f=json&resultRecordCount=10Open this URL in a browser tab to see the raw ArcGIS JSON response.
| Field name | Label | Searchable |
|---|---|---|
| PIN | Parcel Identification Number | YES |
| PARCEL_KEY | Parcel Key (numeric) | YES |
| PARCEL_TYPE | Parcel Type (ORDINARY / CONDO) | NO |
| SRC_CONTROL | Source Control | NO |
369,267 polygon parcels covering the entire county. Verified 2026-05-11: PIN LIKE wildcard queries return ordinary parcels (e.g., '0304 39 0029'). PIN format is space-padded ID with section/block/lot grouping. No owner-name field on this layer — Fairfax keeps ownership data in a separate non-spatial table (per layer description). For owner-name search, see Fairfax County Real Estate Assessment Database (separate web portal, not REST). PARCEL_TYPE distinguishes ORDINARY from CONDO.
Fairfax County GIS Division (Department of Information Technology) — https://www.fairfaxcounty.gov/maps/
/query?where=…&outFields=*&f=jsonto the URL. The sample query above is a working example you can paste into a browser tab to see the raw JSON response.Counties publish parcel data through their own ArcGIS Server installations, each with its own schema. One county uses APN, another uses PIN, a third uses PARCEL_ID. Some expose owner names; others keep them on a separate assessor's portal. The searchable fields list above reflects what this county actually publishes — not what you might expect from a national standard (there isn't one).
For background, see What is an APN?
Many county servers allow public reads but block browser cross-origin requests. The UrbanKit parcel lookup tool fetches directly from your browser; if it works there, the layer is technically public. For your own integration, you may need a same-origin proxy or server-side fetch.
Possibly — counties move services without warning. We re-verify entries weekly and flag stale ones. If you're seeing a fresh 404, please let us know and we'll update the listing.
Most are. Public ArcGIS layers don't typically rate-limit individual reads, but heavy programmatic use can trigger throttling at the host level. Be respectful — query what you need.