St. Charles County, MO parcel and infrastructure data API

Parcel coverage in St. Charles County

About 170,000 parcel records with boundaries, situs addresses and parcel numbers, with the latest source update from October 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. 99% of St. Charles County records carry an owner name.

Infrastructure in and around St. Charles County

Example requests for St. Charles 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 8201 MEXICO RD, ST. PETERS, 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=8201 MEXICO RD, ST. PETERS, MO' \
  https://api.korzy.co/api/search

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/search",
    params={"q": "8201 MEXICO RD, ST. PETERS, 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": "29183-a51f861d65d6eb13f9fd",
      "address": "8201 MEXICO RD",
      "city": "ST. PETERS",
      "postcode": "63376",
      "county": "St. Charles",
      "statefp": "29",
      "longitude": -90.67691808992137,
      "latitude": 38.788433100000006,
      "match_type": "exact",
      "parcelid": "2-0061-S034-00-0004 3100000",
      "parceladdr": "8201 MEXICO RD",
      "parcelcity": "ST. PETERS",
      "situs_zip": "63376",
      "usedesc": "IMPROVED COMMERCIAL (C)",
      "land_use_code": "353",
      "yearbuilt": 2000,
      "bldgsqft": 6953,
      "taxacres": 1.79,
      "totalvalue": 0,
      "market_value_usd": 995743,
      "saledate": "2025-03-06",
      "saleamt": 3500000,
      "updated": "2026-10-26",
      "geoid": "29183"
    }
  ],
  "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, 29183-a51f861d65d6eb13f9fd, in records. 1 credit per 10 records requested.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-90.676918' \
  --data-urlencode 'latitude=38.788433' \
  --data-urlencode 'limit=5' \
  https://api.korzy.co/api/query/point

const params = new URLSearchParams({"longitude": "-90.676918", "latitude": "38.788433", "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=-90.676918' \
  --data-urlencode 'latitude=38.788433' \
  https://api.korzy.co/api/utilities/context

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/utilities/context",
    params={"longitude": "-90.676918", "latitude": "38.788433"},
    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": -90.676918,
  "latitude": 38.788433,
  "matches": {
    "water": [
      {
        "feature_id": "water:41084",
        "name": "MO AMERICAN ST LOUIS ST CHARLES COUNTIES",
        "boundary_basis": "System Sourced"
      }
    ],
    "sewer": [
      {
        "feature_id": "sewer:1071",
        "name": "O'Fallon STP",
        "boundary_basis": "Sourced"
      }
    ]
  },
  "nearby_treatment": [
    {
      "feature_id": "treatment:5897",
      "name": "Spencer Creek STP",
      "distance_km": 6.344713460421972
    },
    {
      "feature_id": "treatment:5895",
      "name": "O'Fallon STP",
      "distance_km": 6.357926969589993
    }
  ]
}

St. Charles County data questions

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

About 150,000 of about 170,000 parcel records (88%) include year built.

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

Yes. 99% of St. Charles 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. Charles County?

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

How much power generation is in St. Charles County?

2 operable power plants in St. Charles County total about 1,100 MW of nameplate capacity, mainly coal and solar.

Which water systems serve St. Charles County?

Service areas of about 20 community water systems cover about 62% of St. Charles County, and sewer service areas cover about 32%. /api/utilities/context returns the water and sewer matches at a point.

More featured counties

• St. Louis County, MOBorders St. Charles County · about 400,000 parcels
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