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Data center campus · Cornerstone business park, Peterson Road west of Route 83, Grayslake, Lake County, Illinois

T5 @ Chicago IV (Grayslake campus)

Under construction as of Sept. 1, 2026

A planned campus of up to 18 buildings in Grayslake that the village approved in phases from 2024 to 2025, now under construction amid opposition and a wetlands review. Also known as: T5@Chicago IV, Cornerstone business park data center campus.

Cite← Illinois data centers
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Power1,200MW reported · stated
Floor area1.01e+07sq ft
Site472acres

Who is behind it

ProjectT5 @ Chicago IV (Grayslake campus)Also: T5@Chicago IV, Cornerstone business park data center campus
Developer and teamT5 Data Centers
End userNot found in the recordsNot yet named in any record or credited report we have found.

The record, newest first

  1. Grayslake issued the building permit for the first 800,000-square-foot building on a campus of up to 472 acres. (Daily Herald, Sept. 1, 2026; Blackridge Research, Sept. 20, 2026)

  2. Lake County reported that T5 had sought permits to fill 16 to 26 acres of wetlands and then volunteered to suspend that application indefinitely; the county noted it has no jurisdiction over the Grayslake project. (Lake County, Illinois, Aug. 14, 2026; Lake County, Illinois, June 11, 2026; Lake County, Illinois, Sept. 8, 2026)

  3. The campus had grown to more than 490 developable acres after unanimous village approvals of each phase; site work, the first three buildings and a substation were under way. (Daily Herald, Oct. 11, 2025)

  4. The site lies in the Cornerstone business park, which the village approved in 2009 and which was already zoned for the use, so only site and building permits were needed. (Daily Herald, June 5, 2024)

  5. T5 announced a 160-acre Grayslake campus that could reach 480 MW, with the first building due in late 2027. (DatacenterDynamics, May 3, 2024)

Conflicts and open questions

  • Coordinates approximate, based on the reported Peterson Road and Route 83 location.
  • Acreage reported as 160 (2024), more than 490 developable (2025), and 472-473 (2026); square footage up to 10.1 million.
  • Lake County's unincorporated-area moratorium (Sept. 8, 2026) does not apply to this site, which lies inside Grayslake.

The full record

Status note
Grayslake issued the building permit for the first 800,000-square-foot building; site work and a ComEd substation were already under way.
Power note
Developer and reporting figures have grown: 480 MW of IT capacity on 160 acres when announced in May 2024; 1.2 GW available to customers (with 1.5 GW secured from ComEd) by October 2025; about 1.55 GW of electrical demand per a September 2026 report. Range 480-1,550 MW across sources.
Evidence
Primary public records
Size class
50 MW or more (tracker scope)
Map position approximate, from the reported address or area. Updated Oct. 17, 2026.