Public ArcGIS MapServer endpoint for St. Clair County parcel data. URL, supported fields, and a working sample query — copy it, or open it directly in the UrbanKit parcel lookup tool.
https://arcgispublicmap.co.st-clair.il.us/server/rest/services/SCC_parcel_map_data/MapServer/29/query?where=UPPER(owner) LIKE UPPER('%SMITH%')&outFields=parcel_number,parcelid,owner,siteadr1,sitecity&returnGeometry=false&f=json&resultRecordCount=10Open this URL in a browser tab to see the raw ArcGIS JSON response.
| Field name | Label | Searchable |
|---|---|---|
| parcel_number | Parcel Number | YES |
| parcelid | Parcel ID | YES |
| owner | Owner Name | YES |
| siteadr1 | Site Address (line 1) | YES |
| sitecity | Site City | YES |
| address | Mailing Address | YES |
St. Clair County is Illinois's 8th most populous (Metro East / Greater St. Louis area, county seat Belleville). The SCC_parcel_map_data MapServer is a 31-layer cadastral service; layer 29 (Parcels, 147k+ features) is the polygon parcel layer with 50+ fields including parcel_number, parcelid, owner, address, address2, cityst, zipcode, siteadr1, siteadr2, sitenum/sitepref/sitename/sitetype/sitesuff/siteunit, sitecity/sitest/sitezip, legal1-4, subdiv, twp/twpname, tcacode, class, landuse. Owner-name search via UPPER() LIKE on owner works. Other layers in the service are annotation layers (layers 0-28) and Roads (layer 30). The county GIS data pricing page notes bulk shapefile/geodatabase downloads are paid; the live REST query API is free.
St. Clair County GIS Department — https://www.co.st-clair.il.us/departments/gis
/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.