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 /api/parcel-record. 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.
Plant details: /api/power/plants/{plant_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 a point: /api/utilities/context
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 of a point: /api/datacenters/context
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%.
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 of a point: /api/logistics/context
Example requests for Cook 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 400 N MONTICELLO AVE, CHICAGO, IL 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=400 N MONTICELLO AVE, CHICAGO, IL' \
https://api.korzy.co/api/searchPython
import os
import requests
response = requests.get(
"https://api.korzy.co/api/search",
params={"q": "400 N MONTICELLO AVE, CHICAGO, IL"},
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"])Response (trimmed)
{
"results": [
{
"korzy_id": "17031-7d1d1cd16c16a9e30f08",
"address": "400 N MONTICELLO AVE",
"city": "CHICAGO",
"postcode": "60624",
"county": "Cook",
"statefp": "17",
"longitude": -87.71769010136913,
"latitude": 41.88866705,
"match_type": "exact",
"parcelid": "16111320430000",
"parceladdr": "400 N MONTICELLO AVE",
"parcelcity": "CHICAGO",
"situs_zip": "60624",
"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",
"geoid": "17031"
}
],
"truncated": false
}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, 17031-7d1d1cd16c16a9e30f08, in records. 1 credit per 10 records requested.
curl --fail-with-body -sS --get \
-H "Authorization: Bearer $KORZY_API_KEY" \
--data-urlencode 'longitude=-87.71769' \
--data-urlencode 'latitude=41.888667' \
--data-urlencode 'limit=5' \
https://api.korzy.co/api/query/pointJavaScript
const params = new URLSearchParams({"longitude": "-87.71769", "latitude": "41.888667", "limit": "5"});
const response = await fetch(`https://api.korzy.co/api/query/point?${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 nearby data-center projects
/api/datacenters/context lists data-center projects within 10 km of the point, nearest first. 1 credit per 10 records requested.
curl --fail-with-body -sS --get \
-H "Authorization: Bearer $KORZY_API_KEY" \
--data-urlencode 'longitude=-87.71769' \
--data-urlencode 'latitude=41.888667' \
--data-urlencode 'radius_km=10' \
--data-urlencode 'limit=3' \
https://api.korzy.co/api/datacenters/contextPython
import os
import requests
response = requests.get(
"https://api.korzy.co/api/datacenters/context",
params={"longitude": "-87.71769", "latitude": "41.888667", "radius_km": "10", "limit": "3"},
headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
timeout=30,
)
response.raise_for_status()
for project in response.json()["projects"]:
print(project["name"], project["status"], project["distance_km"])Response (trimmed)
{
"projects": [
{
"project_id": "dc_0135b689c35dbf970ec4",
"name": "Metro Edge IMD1",
"operator": "Metro Edge Development Partners",
"status": "permitted",
"city": "Chicago",
"state": "IL",
"longitude": -87.6749686,
"latitude": 41.8639696,
"location_precision": "approximate",
"planned_mw": 53,
"distance_km": 4.478037531536522
},
{
"project_id": "dc_7ca920f31fdebefacd47",
"name": "Menlo Digital Chicago Exchange (601 West Polk)",
"operator": "Menlo Digital (Menlo Equities)",
"status": "operating",
"city": "Chicago",
"state": "IL",
"longitude": -87.6430697,
"latitude": 41.8716062,
"location_precision": "exact",
"operational_mw": 8,
"distance_km": 6.462495686148243
},
{
"project_id": "dc_6330e8afd1a62f6b8dd4",
"name": "QTS Chicago 1",
"operator": "QTS Data Centers",
"status": "operating",
"city": "Chicago",
"state": "IL",
"longitude": -87.6689701,
"latitude": 41.8422152,
"location_precision": "approximate",
"distance_km": 6.5540819392691025
}
],
"radius_km": 10,
"limit": 3,
"truncated": true
}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. /api/datacenters/context lists projects within 10 km of any 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%. /api/utilities/context returns the water and sewer matches at a 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
Search, point and record lookups work the same in every county Korzy covers. Credits are shared across parcels, utilities, environment, logistics and data-center routes.