Static snapshot. This site serves two different things: 1,853 data centres reported by OpenStreetMap contributors nationwide, and 13 sites Helios infers from Arizona parcel records, exported on July 29, 2026. The first is a map of what has been recorded; the second is an argued hypothesis with an evidence chain. This is a point-in-time export, not a live view. See meta.json or the methodology.

Cook County

County in IL · 30 data centres recorded in OpenStreetMap

Mapped facilities
30
on the map today
Floor area
0.37
km² across 23 buildings
Share of US load
404
MW, inferred upper bound
Water
0.88
million gal/day, inferred
1 of these 30 are not mapped as buildings, so no power figure is estimated for them. 1 is a campus boundary covering 0.20 km² of land. The megawatt figure above divides a national total by building floor area, and the area of a land parcel is not floor area. A site still being built consumed none of the electricity that total measures. Both are counted here and left out of the estimate rather than folded into it, so this region's load is understated by however much those represents.

When these appeared on the map

observed, not surveyed
01530201720182019202120222023202420252026
Data centres recorded in OpenStreetMap at the end of each month. The hatched stretch is before 2017-01, when telecom=data_center was not yet in common use — the near-zero readings there describe the tag, not the country. This is a count of what has been mapped, and OpenStreetMap carries no construction dates.

What the grid here looks like

reported by OSM contributors
Substations
148
69 kV and above
Bulk substations
18
230 kV and above
Highest voltage
345
kV, present in this county
Generating capacity
1,295
MW across 36 plants

A facility drawing hundreds of megawatts connects at bulk transmission voltage, so the second figure matters more than the first: forty 69 kV yards are not a substitute for one 500 kV substation. 21 of the plants here carry no capacity tag, so the megawatt total is a floor rather than the region's output.

Proximity is not connection. Nothing here shows that any facility has contracted power from any of these substations. That gets settled in interconnection filings Helios cannot read, and in several regions those queues now run for years. A county showing no substations may have none mapped rather than none standing.

Largest named mapped records

by mapped area
NameOperatorMapped asMapped area m²Share MWFirst mapped
Microsoft Data Center - Hoffman Estatesnot recordedCampus boundary195,5862025-03-19
Digital Realty CH1Digital RealtyBuilding43,64247.82023-05-19
Digital Realty CH3Digital RealtyBuilding32,35135.52023-05-19
Microsoft - Azure DatacenterMicrosoftBuilding28,50031.22018-04-10
Digital Realty CH2Digital RealtyBuilding28,14730.92023-11-29
STACK Chicago CHI01Stack InfrastructureBuilding27,72930.42023-05-19
QTS ChicagoQuality Technology ServicesBuilding24,81627.22017-10-16
Stream Chicago IIStreamBuilding20,06022.02023-11-29
Aligned Data Center - Chicago ORD-01AlignedBuilding18,07419.82025-06-18
Skybox Chicago ISkyboxBuilding16,21917.82023-11-29
T5 Chicago IIT5 Data CentersBuilding15,16516.62023-11-29
Equinix Chicago CH3EquinixBuilding12,61613.82023-11-29
Lakeside Technology Centernot recordedBuilding11,99913.22022-02-14
Stream Chicago IStreamBuilding11,20612.32023-11-29
EdgeConneX CHI01EdgeConneXBuilding11,16612.22023-05-19
Aligned Data Center - Chicago ORD-02AlignedBuilding10,35211.32025-06-18
Iron Mountain Data & Record StorageIron MountainBuilding9,85110.82021-01-21
Digital Realty Chicago ORD12Digital RealtyBuilding8,3779.22023-05-19
EdgeConneX CHI02EdgeConneXBuilding5,9796.52023-11-29
CoreSite Chicago Data Center (CH2)CoreSiteBuilding5,7396.32020-09-15
Serverfarm CH1ServerfarmBuilding5,2425.72023-02-07
Digital Realty ORD11Digital RealtyBuilding8450.92024-10-30
NetralityNetralityPoint2023-01-10
Digital Realty ORD10Digital RealtyPoint2023-05-19
Centersquare Chicago Data Center - ORD1CentersquarePoint2023-05-19
West Monroenot recordedPoint2023-06-01
CoreSite Chicago Data Center (CH1)CoreSitePoint2023-08-08
Equinix Chicago Data Center - CH1EquinixPoint2025-03-24

“First mapped” is when OpenStreetMap recorded the facility, not when it was built — OpenStreetMap carries no construction dates. Mapped area means a building floor plate, campus boundary, or construction polygon according to the “Mapped as” column; those quantities are never added together. The megawatt column appears only for buildings and is their floor-area share of a reported national total, not a measurement.