St. Louis County, MO parcel and infrastructure data API

Parcel coverage in St. Louis County

About 400,000 parcel records with boundaries, situs addresses and parcel numbers, with the latest source update from November 2026. Each record has a stable korzy_id you can store and look up again with /api/parcel-record. Share of records with each field:

Owner name and mailing address are returned with include_owner=true, which doubles a request's cost: a parcel record costs 2 credits instead of 1. 95% of St. Louis County records carry an owner name.

Infrastructure in and around St. Louis County

Example requests for St. Louis County

Real responses from the production API, trimmed to the main fields. Every request needs an API key with api:read; see authentication and credits and limits.

1. Find a parcel by address

/api/search matches 1264 ARCH TER, ARCH TERRACE, MO and returns the parcel's korzy_id, coordinates and record. 1 credit.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'q=1264 ARCH TER, ARCH TERRACE, MO' \
  https://api.korzy.co/api/search

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/search",
    params={"q": "1264 ARCH TER, ARCH TERRACE, MO"},
    headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
    timeout=30,
)
response.raise_for_status()
parcel = response.json()["results"][0]
print(parcel["korzy_id"], parcel["longitude"], parcel["latitude"])

{
  "results": [
    {
      "korzy_id": "29189-25e23c77bebf38912ce3",
      "address": "1264 ARCH TER",
      "city": "ARCH TERRACE",
      "postcode": "63117",
      "county": "St. Louis",
      "statefp": "29",
      "longitude": -90.3278469735438,
      "latitude": 38.63086405022659,
      "match_type": "exact",
      "parcelid": "20J421431",
      "parceladdr": "1264 ARCH TER",
      "parcelcity": "ARCH TERRACE",
      "situs_zip": "63117",
      "usedesc": "Institution",
      "yearbuilt": 1928,
      "bldgsqft": 6430,
      "taxacres": 2.07,
      "totalvalue": 1647490,
      "land_value_usd": 1803400,
      "improvement_value_usd": 4505100,
      "assessed_value_usd": 1946100,
      "market_value_usd": 6308500,
      "updated": "2026-01-01",
      "geoid": "29189"
    }
  ],
  "truncated": false
}

With include_owner=true (2 credits) the record adds owner fields, shown here as placeholders:

{
  "owner_name": "EXAMPLE HOLDINGS LLC",
  "owner_mailing_address": "100 EXAMPLE ST, SAMPLE CITY, ST 00000"
}

2. Look up the parcel at a point

/api/query/point returns every parcel whose boundary covers the coordinates; here it returns the same record, 29189-25e23c77bebf38912ce3, in records. 1 credit per 10 records requested.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-90.327847' \
  --data-urlencode 'latitude=38.630864' \
  --data-urlencode 'limit=5' \
  https://api.korzy.co/api/query/point

const params = new URLSearchParams({"longitude": "-90.327847", "latitude": "38.630864", "limit": "5"});
const response = await fetch(`https://api.korzy.co/api/query/point?${params}`, {
  headers: { Authorization: `Bearer ${process.env.KORZY_API_KEY}` },
});
if (!response.ok) throw new Error(`Korzy API ${response.status}`);
const { records } = await response.json();
console.log(records.map((record) => record.korzy_id));

3. Check water and sewer service

/api/utilities/context returns the water and sewer service areas at the point and the nearest treatment plants. 1 credit.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-90.327847' \
  --data-urlencode 'latitude=38.630864' \
  https://api.korzy.co/api/utilities/context

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/utilities/context",
    params={"longitude": "-90.327847", "latitude": "38.630864"},
    headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
    timeout=30,
)
response.raise_for_status()
matches = response.json()["matches"]
print([area["name"] for area in matches["water"]])

{
  "longitude": -90.327847,
  "latitude": 38.630864,
  "matches": {
    "water": [
      {
        "feature_id": "water:41084",
        "name": "MO AMERICAN ST LOUIS ST CHARLES COUNTIES",
        "boundary_basis": "System Sourced"
      }
    ],
    "sewer": [
      {
        "feature_id": "sewer:1035",
        "name": "Lemay WWTP",
        "boundary_basis": "Sourced"
      }
    ]
  },
  "nearby_treatment": [
    {
      "feature_id": "treatment:5761",
      "name": "Lemay WWTP",
      "distance_km": 11.984348600861415
    },
    {
      "feature_id": "treatment:15247",
      "name": "MDC Powder Valley Nature Center WWTP",
      "distance_km": 12.050752447444532
    }
  ]
}

St. Louis County data questions

How many parcels in St. Louis County include year built?

About 390,000 of about 400,000 parcel records (97%) include year built.

Does the Korzy API return owner names for St. Louis County parcels?

Yes. 95% of St. Louis County parcel records carry an owner name. Add include_owner=true to a point, search or parcel-record request; it doubles the request's cost, so a single parcel record costs 2 credits.

How many data-center projects are in St. Louis County?

Korzy tracks 2 data-center projects in St. Louis County: 1 operating and 1 proposed. /api/datacenters/context lists projects within 10 km of any point.

Which water systems serve St. Louis County?

Service areas of about 20 community water systems cover about 75% of St. Louis County, and sewer service areas cover about 87%. /api/utilities/context returns the water and sewer matches at a point.

How much of St. Louis County is in a mapped flood zone?

About 16% of St. Louis County's area falls within special flood hazard areas on the current federal flood maps.

More featured counties

• St. Charles County, MOBorders St. Louis County · about 170,000 parcels
• Jackson County, MOabout 300,000 parcels

All featured Missouri counties