Public ArcGIS MapServer endpoint for King County parcel data. URL, supported fields, and a working sample query — copy it, or open it directly in the UrbanKit parcel lookup tool.
https://gismaps.kingcounty.gov/arcgis/rest/services/Property/KingCo_Parcels/MapServer/0PINParcel Identification NumberMAJORMajor (first 6 of PIN)MINORMinor (last 4 of PIN)curl -s 'https://gismaps.kingcounty.gov/arcgis/rest/services/Property/KingCo_Parcels/MapServer/0/query?where=PIN%3D%270000200001%27&outFields=*&f=json'
https://gismaps.kingcounty.gov/arcgis/rest/services/Property/KingCo_Parcels/MapServer/0/query?where=PIN='0000200001'&outFields=*&f=jsonOpen this URL in a browser tab to see the raw ArcGIS JSON response.
| Field name | Label | Searchable |
|---|---|---|
| PIN | Parcel Identification Number | YES |
| MAJOR | Major (first 6 of PIN) | YES |
| MINOR | Minor (last 4 of PIN) | YES |
King County, Washington (Seattle metro, pop. 2.3M, county seat Seattle) is the most populous Washington county, containing Seattle, Bellevue, Redmond, Renton, and Kent. The KingCo_Parcels MapServer layer publishes parcel polygons with three identifier fields: PIN (10-digit Parcel Identification Number), MAJOR (first 6 digits of PIN, identifying the parcel block), and MINOR (last 4 digits, the parcel within the block). No owner name, situs address, or assessment values are on this public REST layer. Washington State law broadly restricts owner-name exposure on public REST endpoints; King County follows this consistently. Confirmed live 2026-06-06 -- 638,577 parcels, PIN-searchable. For ownership lookups, use the King County Assessor's eReal Property portal at info.kingcounty.gov/assessor/emap/ (search by address, PIN, or complex name). The interactive Parcel Viewer is at gismaps.kingcounty.gov/parcelviewer2/. Bulk GIS downloads: kingcounty.gov/services/gis/GISData.aspx.
King County GIS Center — https://kingcounty.gov/services/gis.aspx
King County's King County Parcels layer exposes parcel identifiers (Parcel Identification Number, Major (first 6 of PIN), Minor (last 4 of PIN)). Use it for PIN-keyed record pulls (owner-name search lives on a separate assessor system). All 3 listed fields accept queries. Served as an ArcGIS MapServer layer, which supports query operations but not write operations; last verified 2026-06-06.
/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 King 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.