T5 @ Chicago IV data center campus (Grayslake)
Also called: T5@Chicago IV, Cornerstone business park
T5 is building a giant data center campus on 472 acres in Grayslake, with up to 18 buildings and 1,550 megawatts of power from ComEd. It will have diesel backup generators. Daily water use is said to be under 50,000 gallons, but filling the cooling systems at start-up can take millions of gallons.
Where things stand: Village issued the first building permit on Sept. 1, 2026; site work is underway. A lawsuit asks the court to cancel the approvals; a hearing is set for Oct. 30, 2026.
🕒 Latest update (Sept 1, 2026): Village issued the first building permit, for an 800,000-square-foot building.
Lake County Circuit Court. Anyone can come and speak.
What we know
- 📍 WherePeterson Road and Alleghany Road, west of Route 83 (Cornerstone business park), Grayslake, Lake County
- 🏢 CompanyT5 Data Centers
- 🌳 Size472 acres
- ⚡ Power it needs1,550 megawatts (about as much as 1,240,000 homes)
- 🔌 Where the power comes fromComEd; an electrical substation is being built on site.
- 💧 WaterCentral Lake County Joint Action Water Agency (Lake Michigan water) · 50,000 gallons a day
- 💵 Cost$18 billion
- 💸 Tax breaksVillage says there are no local tax breaks or TIF. It projects $1.4 billion in property taxes over 20 years.
- 👷 Jobs promised1,500
❓ Still unanswered
Nobody has answered these in public yet. Can you help find out?
- How many diesel backup generators will the campus have? 🙋 I'll find out
- When exactly did the Village Board approve the plan, and by what vote? 🙋 I'll find out
- How will the court rule on the lawsuit? 🙋 I'll find out
- Which company will use the data centers? 🙋 I'll find out
What happened so far
- Sept 2026A neighbors' group and nine residents sued the village and T5 to void the approvals.
- Sept 1, 2026Village issued the first building permit, for an 800,000-square-foot building.
Local votes and rules
⚖️ Court case
A residents' group and nine residents sued Grayslake, T5 Data Centers and Alter Asset Management. They say village zoning does not allow data centers and that officials made the deal in closed meetings and private emails, against the Open Meetings Act. They want the approvals and the development deal cancelled. The village asked the court to dismiss it.
An aerial photo of the area.
Where this comes from
- Grayslake issues first permit for construction to begin on mega data center campus as lawsuit seeks to block development · Lake and McHenry County Scanner · Sept 1, 2026
- Grayslake erupts as mega data campus plows ahead · Hoodline · May 7, 2026
- T5 secures first permit for $18 billion Grayslake data centre · Blackridge Research · Sept 2026
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