Cook County, IL parcel and infrastructure data API
Korzy has about 1.9 million parcel records for Cook County, Illinois, with source updates through August 2026. Nearly every record carries values and land use; 84% include year built and 78% include building size. In and around the county the API also maps about 60 data-center projects (30 operating and 10 under construction); about 1,200 miles of active rail; and about 40 power plants with about 1,300 MW of capacity, led by natural gas. Look up any parcel by address or coordinates, then check nearby data-center projects, utilities and grid context at the same point.
Parcel coverage in Cook County
About 1.9 million parcel records with boundaries, situs addresses and parcel numbers, with the latest source update from August 2026. Each record has a stable korzy_id you can store and look up again with /v1/records/{id}. Share of records with each field:
| Field | Coverage | Share |
|---|---|---|
| Situs address | Nearly all · 100% | |
| Owner name | Not published | |
| Assessed or market value | Nearly all · 98% | |
| Year built | Most · 84% | |
| Building size | Most · 78% | |
| Last sale | Many · 58% | |
| Land use | Nearly all · 100% | |
| Zoning | Not published |
Cook County records do not include owner names. See pricing for credit costs.
Infrastructure in and around Cook County
Power plants
About 40 operable plants with about 1,300 MW of nameplate capacity; largest by capacity: natural gas, oil, solar. Proposed generators add about 40 MW.
Within 50 km: /v1/lookup section power; details: /v1/records/{id}
Substations and transmission
About 220 in-service substations, about 25 rated 230 kV or higher.
About 880 miles of transmission lines: about 500 mi at 100–161 kV; about 330 mi at 345 kV.
Water and sewer service
Service areas of about 170 community water systems cover about 78% of the county.
Sewer service areas of about 30 systems cover about 95%.
At an address or point: /v1/lookup section utilities
Data-center projects
About 60 tracked projects: 30 operating, 10 under construction, 2 permitted, 2 proposed, 15 status not reported. Reported operating capacity: about 380 MW. Reported planned capacity: about 1,700 MW.
Within 10 km: /v1/lookup section datacenters
Flood zones and wetlands
Special flood hazard areas cover about 7% of the county on the current federal flood maps, published October 2026.
Mapped wetlands cover about 2%.
At an address or point: /v1/lookup section environment
Rail, ports and freight
- About 1,200 miles of active rail, about 620 of it main line
- About 270 miles of national freight network highway
- 2 port areas with reported cargo tonnage
- 15 intermodal rail terminals
Within 25 km: /v1/lookup section logistics
Example requests for Cook County
The lookup response is a real production response, trimmed to the main fields. Every request needs an API key with api:read; see authentication and credits and limits.
1. Find a parcel and nearby data-center projects
/v1/lookup matches 400 N MONTICELLO AVE, CHICAGO, IL and returns the parcel's korzy_id and record, plus the data-center projects within 10 km, nearest first. 2 credits.
curl --fail-with-body -sS \
-H "Authorization: Bearer $KORZY_API_KEY" \
-H "Content-Type: application/json" \
-d '{"address":"400 N MONTICELLO AVE, CHICAGO, IL","sections":["datacenters"]}' \
https://api.korzy.co/v1/lookupPython
import os
import requests
response = requests.post(
"https://api.korzy.co/v1/lookup",
json={"address": "400 N MONTICELLO AVE, CHICAGO, IL", "sections": ["datacenters"]},
headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
timeout=60,
)
response.raise_for_status()
body = response.json()
parcel = body["parcels"]["records"][0]
print(parcel["korzy_id"], body["sections"]["datacenters"]["status"])Production response (trimmed)
{
"location": {
"longitude": -87.71769010136913,
"latitude": 41.88866705,
"address": "400 N MONTICELLO AVE, CHICAGO",
"match_type": "exact"
},
"parcels": {
"records": [
{
"id": "17031-7d1d1cd16c16a9e30f08",
"korzy_id": "17031-7d1d1cd16c16a9e30f08",
"parcelid": "16111320430000",
"parceladdr": "400 N MONTICELLO AVE",
"parcelcity": "CHICAGO",
"situs_zip": "60624",
"statefp": "17",
"geoid": "17031",
"longitude": -87.71769010136913,
"latitude": 41.88866705,
"usedesc": "Commercial/Industrial",
"land_use_code": "597",
"yearbuilt": 1969,
"bldgsqft": 6604,
"taxacres": 0.8406106519742883,
"totalvalue": 986375,
"saledate": "2018-10-01",
"saleamt": 13000,
"updated": "2026-01-01"
}
],
"truncated": false
},
"sections": {
"datacenters": {
"status": "ok",
"data": {
"radius_km": 10,
"projects": [
{
"id": "datacenter:dc_0135b689c35dbf970ec4",
"project_id": "dc_0135b689c35dbf970ec4",
"name": "Metro Edge IMD1",
"operator": "Metro Edge Development Partners",
"status": "permitted",
"state": "IL",
"city": "Chicago",
"address": "1951 W Hastings St",
"longitude": -87.6749686,
"latitude": 41.8639696,
"location_precision": "approximate",
"planned_mw": 53,
"source_count": 1,
"source_date": "2026-09-25",
"mapped": true,
"distance_km": 4.478047569328447
},
{
"id": "datacenter:dc_7ca920f31fdebefacd47",
"project_id": "dc_7ca920f31fdebefacd47",
"name": "Menlo Digital Chicago Exchange (601 West Polk)",
"operator": "Menlo Digital (Menlo Equities)",
"status": "operating",
"state": "IL",
"city": "Chicago",
"address": "601 W Polk Street",
"longitude": -87.6430697,
"latitude": 41.8716062,
"location_precision": "exact",
"operational_mw": 8,
"source_count": 1,
"source_date": "2026-09-25",
"mapped": true,
"distance_km": 6.4625053384761095
},
{
"id": "datacenter:dc_6330e8afd1a62f6b8dd4",
"project_id": "dc_6330e8afd1a62f6b8dd4",
"name": "QTS Chicago 1",
"operator": "QTS Data Centers",
"status": "operating",
"state": "IL",
"city": "Chicago",
"address": "2800 S Ashland Ave",
"longitude": -87.6689701,
"latitude": 41.8422152,
"location_precision": "approximate",
"source_count": 1,
"source_date": "2026-09-21",
"mapped": true,
"distance_km": 6.554091487033521
}
],
"truncated": true,
"note": "Straight-line distance to the reported project point; inspect location_precision. Projects merge supported source matches, not every nearby building. Approximate locations do not identify a parcel. Reported IT load, facility power, planned capacity and estimates remain separate source claims. No record or unknown status does not establish absence or inactivity."
},
"provenance": [
{
"dataset": "datacenters",
"as_of": "2026-11-02",
"data_version": "20261102T123021962884Z"
}
]
}
},
"credits": {
"charged": 2,
"refunded": 0
}
}2. Add value and sale fields
/v1/enrich returns the fields you choose for up to 25 parcels per request; here the parcel 17031-7d1d1cd16c16a9e30f08. 1 credit.
curl --fail-with-body -sS \
-H "Authorization: Bearer $KORZY_API_KEY" \
-H "Content-Type: application/json" \
-d '{"items":[{"korzy_id":"17031-7d1d1cd16c16a9e30f08"}],"fields":["identity","value","sale"]}' \
https://api.korzy.co/v1/enrich3. Fetch the record again by ID
/v1/records/{id} returns the stored parcel's full record, without owner fields. 1 credit.
curl --fail-with-body -sS \
-H "Authorization: Bearer $KORZY_API_KEY" \
https://api.korzy.co/v1/records/17031-7d1d1cd16c16a9e30f08JavaScript
const response = await fetch(`https://api.korzy.co/v1/records/${encodeURIComponent("17031-7d1d1cd16c16a9e30f08")}`, {
headers: { Authorization: `Bearer ${process.env.KORZY_API_KEY}` },
});
if (!response.ok) throw new Error(`Korzy API ${response.status}`);
const { record } = await response.json();
console.log(record.parceladdr, record.usedesc);Cook County data questions
- How many parcels in Cook County include year built?
- About 1.6 million of about 1.9 million parcel records (84%) include year built.
- Does the Korzy API return owner names for Cook County parcels?
- Cook County parcel records do not include owner names. Values, land use and building facts are returned where the county publishes them.
- How many data-center projects are in Cook County?
- Korzy tracks about 60 data-center projects in Cook County: 30 operating, 15 status not reported and 10 under construction. A /v1/lookup with the datacenters section lists projects within 10 km of any address or point.
- How much power generation is in Cook County?
- About 40 operable power plants in Cook County total about 1,300 MW of nameplate capacity, mainly natural gas, oil and solar.
- Which water systems serve Cook County?
- Service areas of about 170 community water systems cover about 78% of Cook County, and sewer service areas cover about 95%. A /v1/lookup with the utilities section returns the water and sewer matches at an address or point.
More featured counties
- DuPage County, ILBorders Cook County · about 340,000 parcels
- Lake County, ILBorders Cook County · about 320,000 parcels
Build on Cook County parcel data
Lookups, enrichment and records work the same in every county Korzy covers. Credits are shared across parcels, utilities, environment, logistics, power, grid, data-center and terrain sections.