Data centers in Lake County, Illinois: 1 project mapped

Imagery: Esri, Maxar

Grayslake's data center grew roughly threefold between its 2024 announcement and its 2025 approval, and many neighbors say they only noticed once building began. T5 Data Centers first proposed a 160-acre site with a first building due in late 2027 and up to 480 megawatts of power eventually. By the time the Grayslake Village Board finished approving "T5 @ Chicago IV" in May 2025, it covered up to 472 acres and more than 10 million square feet, with an electrical demand of about 1.55 gigawatts from the utility ComEd, according to a residents' lawsuit. Village officials put the investment at about $18 billion and projected $1.4 billion in property tax over 20 years.

Neighbors say they were kept in the dark. On July 31, 2026, the Preservation of Community Well-being Collective LLC and nine residents sued the village, T5 and landowner Alter Group in Lake County Circuit Court to void the approvals, saying public notices used only the code name "T5@Chicago IV" and did not disclose the project's scale until the last agenda. "It is about whether a village of just over 20,000 people ... can approve a project of unprecedented scale in a way that materially affects thousands of neighbors," said the plaintiffs' attorney, Chloe A. Russell. Just before the suit was filed, T5 suspended its wetlands permit application, citing "community questions and concerns."

The Lake County Board, which has no say inside Grayslake, voted on September 8, 2026 to ban new data centers in unincorporated Lake County until May 11, 2027, after a hearing that drew two hours of testimony and more than 1,000 written comments. "We are taking pressure from every side of this issue, but at the end of the day, we choose our citizens," said board member Esiah Campos. Grayslake issued its first building permit in early September, for an 800,000-square-foot building, so construction has begun. The lawsuit's first status hearing is set for October 30 in Lake County Circuit Court.

Every project above is drawn from public records, filings and local reporting. Each row links to what it is based on. Statuses change, so check the source date before you rely on one. Found something wrong? Write to [email protected] and it gets fixed.