Public ArcGIS MapServer endpoint for St. Louis County parcel data. URL, supported fields, and a working sample query, copy it, or open it directly in the UrbanKit parcel lookup tool.
https://maps.stlouisco.com/hosting/rest/services/Maps/AGS_Parcels/MapServer/0LOCATORParcel Locator NumberPARENT_LOCParent LocatorOWNER_NAMEOwner NameOWN_ADDOwner AddressOWN_CITYOwner CityOWN_STATEOwner StateOWN_ZIPOwner ZIPPROP_ADDProperty AddressPROP_ZIPProperty ZIPcurl -s 'https://maps.stlouisco.com/hosting/rest/services/Maps/AGS_Parcels/MapServer/0/query?where=UPPER(OWNER_NAME)%20LIKE%20UPPER('%25SMITH%25')&outFields=LOCATOR,OWNER_NAME,PROP_ADD&returnGeometry=false&f=json&resultRecordCount=10'https://maps.stlouisco.com/hosting/rest/services/Maps/AGS_Parcels/MapServer/0/query?where=UPPER(OWNER_NAME) LIKE UPPER('%SMITH%')&outFields=LOCATOR,OWNER_NAME,PROP_ADD&returnGeometry=false&f=json&resultRecordCount=10Open this URL in a browser tab to see the raw ArcGIS JSON response.
| Field name | Label | Searchable |
|---|---|---|
| LOCATOR | Parcel Locator Number | YES |
| PARENT_LOC | Parent Locator | YES |
| OWNER_NAME | Owner Name | YES |
| OWN_ADD | Owner Address | YES |
| OWN_CITY | Owner City | YES |
| OWN_STATE | Owner State | YES |
| OWN_ZIP | Owner ZIP | YES |
| PROP_ADD | Property Address | YES |
| PROP_ZIP | Property ZIP | YES |
| PROPCLASS | Property Class | NO |
St. Louis County MO (St. Louis metro west/south, county seat Clayton, NOT the independent City of St. Louis) provides AGS_Parcels/MapServer/0 with 30+ fields: LOCATOR (parcel ID), PARENT_LOC, TAXYR, OWNER_NAME, PROP_ADRNUM, PROP_ADD, PROP_ZIP, OWN_ADD, OWN_CITY, OWN_STATE, OWN_ZIP, SCHSUB (school subdivision), MUNYCODE (municipality code), TAXCODE, ASSTIMPVAL, TOTASSMT, APPLANDVAL, APPIMPVAL, TOTAPVAL, PROPCLASS, LUC, LANDUSE2, LUCODE, TENURE, BLDGNAME, TWPNAME. Query confirmed live: UPPER(OWNER_NAME) LIKE '%SMITH%' returns real results (e.g., 'SMITH KIMBERLY & ANTHONY T/E' at '11041 LILAC AVE'). St. Louis County MO (FIPS 29189) is a separate entity from the City of St. Louis (FIPS 29510, an independent city not part of any county). The GeoData portal at data-stlcogis.opendata.arcgis.com provides open data downloads and GeoServices API links. The maps.stlouisco.com server is the live REST host.
St. Louis County Geospatial Data Center, https://gis.stlouiscountymo.gov/
St. Louis County's Parcels layer exposes owner names (Owner Name, Owner Address, Owner City, Owner State, Owner ZIP) and address fields (Property Address). Use it for owner-name lookups and address-based parcel searches. 9 of 10 listed fields accept queries; the rest are returned on read but not indexed for search. Served as an ArcGIS MapServer layer, which supports query operations but not write operations; last verified 2026-05-15.
/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 St. Louis County actually publishes, not what you might expect from a national standard (there isn't one).
For background, see What is an APN?
maps.stlouisco.com serves St. Louis County, Missouri parcels over public ArcGIS REST, but, like most county servers, it may not send the CORS headers a browser needs for a cross-origin fetch. If a direct browser call fails, the layer still works from curl, Postman, or a server-side script; the UrbanKit parcel lookup tool proxies the request, so a search that succeeds there confirms the layer is genuinely public.
We last verified St. Louis County's MapServer layer on 2026-05-15. County GIS teams move services without notice, so if you hit a fresh 404, tell us and we'll re-check. Atlas entries are re-verified on a rolling basis.
St. Louis County's layer is hosted by the county on maps.stlouisco.com. Public ArcGIS endpoints rarely rate-limit individual reads, but maps.stlouisco.com can throttle heavy automated traffic at the host level. Page through results with resultOffset / resultRecordCount and request only the fields you need. There's no API key and no charge from the county.