Substation-Adjacent Datacenter Sites in Illinois
At a glance
Parcels sited next to existing transmission substations. Co-location with a substation is the single strongest speed-to-power signal — interconnection distance is measured in feet, not miles.
Top substation-adjacent sites in Illinois
| Site | Type | County | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|---|
| UNKNOWN122269 | Substation-Adjacent | Cook County | 345 kV | 600 MW | 4.8 yrs | 70.3 |
| UNKNOWN121936 | Substation-Adjacent | Kenosha County | 345 kV | 600 MW | 4.8 yrs | 69.5 |
| UNKNOWN124436 | Substation-Adjacent | Cook County | 345 kV | 600 MW | 4.8 yrs | 69.3 |
| UNKNOWN133790 | Substation-Adjacent | Lake County | 345 kV | 600 MW | 4.8 yrs | 67.8 |
| UNKNOWN122285 | Substation-Adjacent | Cook County | 345 kV | 600 MW | 4.8 yrs | 67.6 |
| CAHOKIA | Substation-Adjacent | St. Louis city | 345 kV | 600 MW | 4.8 yrs | 67.6 |
| SUB 39 | Substation-Adjacent | Rock Island County | 345 kV | 600 MW | 4.8 yrs | 67.2 |
| PLANO (765 KV) | Substation-Adjacent | Kendall County | 765 kV | 1,000 MW | 4.8 yrs | 67.0 |
| FARGO 345 KV | Substation-Adjacent | Peoria County | 345 kV | 600 MW | 4.8 yrs | 66.6 |
| RISER159741 | Substation-Adjacent | Tazewell County | 345 kV | 600 MW | 4.8 yrs | 66.6 |
| OAK GROVE | Substation-Adjacent | Rock Island County | 345 kV | 600 MW | 4.8 yrs | 66.6 |
| TAP139481 | Substation-Adjacent | St. Louis city | 345 kV | 600 MW | 4.8 yrs | 66.6 |
| STALLINGS | Substation-Adjacent | Madison County | 345 kV | 600 MW | 4.8 yrs | 66.5 |
| JOLIET | Substation-Adjacent | Will County | 345 kV | 600 MW | 4.8 yrs | 66.5 |
| BALDWIN STATION | Substation-Adjacent | Randolph County | 345 kV | 600 MW | 4.8 yrs | 66.4 |
| POWERTON STATION | Substation-Adjacent | Tazewell County | 345 kV | 600 MW | 4.8 yrs | 66.2 |
| UNKNOWN122603 | Substation-Adjacent | Tazewell County | 345 kV | 600 MW | 4.8 yrs | 66.2 |
| TAZEWELL | Substation-Adjacent | Tazewell County | 345 kV | 600 MW | 4.8 yrs | 66.1 |
| MAPLE RIDGE | Substation-Adjacent | Peoria County | 345 kV | 600 MW | 4.8 yrs | 66.1 |
| UNKNOWN121705 | Substation-Adjacent | St. Louis city | 138 kV | 100 MW | 4.8 yrs | 65.9 |
| COFFEEN | Substation-Adjacent | Bond County | 345 kV | 600 MW | 4.8 yrs | 65.8 |
| JOPPA 345 | Substation-Adjacent | Massac County | 345 kV | 600 MW | 4.8 yrs | 65.5 |
| ELECTRIC LIGHT 345 KV | Substation-Adjacent | DuPage County | 345 kV | 600 MW | 4.8 yrs | 65.2 |
| UNKNOWN122226 | Substation-Adjacent | DuPage County | 345 kV | 600 MW | 4.8 yrs | 65.2 |
| UNKNOWN124699 | Substation-Adjacent | Cook County | 345 kV | 600 MW | 4.8 yrs | 65.2 |
How does Illinois compare with other states for substation-adjacent sites?
With 795 sites, Illinois ranks 22nd of the 52 states that have any substation-adjacent candidate sites. Texas leads with 3,635. Nationally, substation-adjacent sites average 57.4/100 DC Readiness, above the 53.0 average across all site types. Across every site type, Illinois averages 53.6, the 26th-highest of 52 states, and its candidate sites face an average interconnection-queue wait of 4.8 years.
Where are the highest-scoring substation-adjacent sites in Illinois?
The top 25 range from 70.3 to 65.2 on the 0–100 DC Readiness Score. They are concentrated in Cook County (4), Tazewell County (4), St. Louis city (3) and Rock Island County (2). By grid region, 15 are in MISO and 10 are in PJM.
County pages: Cook County · Tazewell County · St. Louis city · Rock Island County
What power, fiber and flood exposure do these substation-adjacent sites have?
Of the top 25 substation-adjacent sites in Illinois, 25 have a recorded nearest-substation voltage, with a median of 345 kV; for 24 that substation is rated 230 kV or higher. Their counties have a median of 12 fixed fiber broadband providers in FCC data. The median distance to the nearest internet exchange facility is 17 km. The median interconnection-queue wait in their markets is 4.8 years. None of the 1 with a mapped FEMA flood zone sits in a high-risk (A or V) zone. 6 lie within 25 km of a binding transmission constraint.
Frequently asked questions
How many substation-adjacent datacenter sites are in Illinois?
GridCensus catalogs 795 substation-adjacent datacenter candidate sites in Illinois, 2% of the national total for this type (22nd of 52 states).
What is a substation-adjacent datacenter site?
Parcels sited next to existing transmission substations. Co-location with a substation is the single strongest speed-to-power signal — interconnection distance is measured in feet, not miles.
What is the best substation-adjacent datacenter site in Illinois?
By DC Readiness Score, UNKNOWN122269 in Cook County ranks first at 70.3/100, followed by UNKNOWN121936 in Kenosha County at 69.5.
Which Illinois counties have the best substation-adjacent sites?
The top 25 substation-adjacent sites in Illinois are concentrated in Cook County (4), Tazewell County (4), St. Louis city (3) and Rock Island County (2).
How does Illinois score for datacenters overall?
All 3,641 scored sites in Illinois average 53.6/100 DC Readiness, the 26th-highest of 52 states, against a national average of 53.0.
More on substation-adjacent sites and Illinois
- All datacenter sites in Illinois· 3,641 sites
- Substation-Adjacent datacenter sites nationwide· 38,820 sites
- Industrial sites in Illinois· 1,441 sites
- Greenfield sites in Illinois· 913 sites
- Former Mine sites in Illinois· 368 sites
- Federal Excess sites in Illinois· 89 sites
- Brownfield sites in Illinois· 33 sites
Substation-Adjacent sites in other states
- Substation-Adjacent sites in Texas· 3,635 sites
- Substation-Adjacent sites in California· 1,573 sites
- Substation-Adjacent sites in Florida· 1,539 sites
- Substation-Adjacent sites in Georgia· 1,530 sites
- Substation-Adjacent sites in Oklahoma· 1,344 sites
- Substation-Adjacent sites in Washington· 1,343 sites
- Substation-Adjacent sites in Minnesota· 1,270 sites
- Substation-Adjacent sites in Kentucky· 1,261 sites
Dataset updated . Screening estimates derived from public data sources.
About this data
Source: GridCensus composite of HIFLD transmission and substation data, EIA, FEMA National Risk Index, FCC broadband data, PeeringDB and ISO interconnection queues, as published November 12, 2026 — GridCensus refreshes it monthly. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “Substation-Adjacent datacenter sites in Illinois”, https://gridcensus.com/site-types/substation/illinois (data as of November 12, 2026).
Go deeper than the public screen
Every site and score for Substation-Adjacent sites in Illinois is free to browse. Pro adds Watchtower on 25 sites, alerts when new candidate sites, datacenters or interconnection-queue requests appear in your markets, score and capacity history, and CSV export. Enterprise adds team seats, weekly data files for all 147,272 sites, the REST API and an MCP server for AI tools.