Atlanta-based T5 Data Centers reached a concrete construction milestone on September 1, 2026, when the Village of Grayslake issued the first building permit for T5 @ Chicago IV, a campus targeting up to 1.55 gigawatts of electrical demand on nearly 473 acres of industrially zoned land in Lake County's Cornerstone business park. The permit covers an 800,000-square-foot initial facility and authorizes site work to begin, as first reported by the Daily Herald and also covered by Patch (Grayslake).

Village approvals granted between September 2024 and May 2025 established the envelope for the full campus. A more recent village-issued plan describes a scaled configuration currently under active development.

The campus sits within the broader Cornerstone mixed-use development, a $750 million, 641-acre project along Peterson Road near Route 83/Alleghany Road. The current 11-building proposal represents roughly 33 percent less building space than earlier concepts.

T5 Data Centers is an Atlanta-based developer and operator specializing in large-scale, AI-ready wholesale and enterprise data center campuses. The company has developed facilities across multiple U.S. markets and positions T5 @ Chicago IV as a next-generation campus built to meet hyperscale and AI workload density requirements.

A campus drawing 1.55GW from a single utility is an infrastructure project in its own right before a single server rack is installed. ComEd substation upgrades, on-site diesel backup generation at that power level, and the civil work required to prepare 473 acres along Peterson Road will consume enormous quantities of switchgear, transformers, conduit, and structural steel. Supply chain lead times on utility-scale electrical equipment are currently measured in years, which means procurement decisions for later phases are being made now even as phase one site work begins.

Active litigation is a material project risk here. On July 31, 2026, the Preservation of Community Well-Being Collective LLC and local residents filed suit in Lake County Circuit Court seeking to invalidate the 2024-2025 approvals and enjoin the village from issuing further permits, as detailed by the Lake & McHenry County Scanner. The village is treating the campus as an approved project and proceeded with the September 1 permit issuance, but the lawsuit introduces schedule uncertainty that has not been resolved.

At 1.55GW and potentially 10 million-plus square feet, T5 @ Chicago IV is among the largest concurrent construction efforts in the greater Chicago region, competing directly with other metro-area projects for electricians, pipefitters, ironworkers, and civil trades. Chicago's unionized building trades provide the depth this project needs, and Lake County's existing base of large pharmaceutical, manufacturing, and distribution employers, including Abbott and Baxter, means the regional maintenance and heavy electrical workforce is already conditioned to complex, large-facility environments. The non-obvious staffing dynamic here is the litigation overhang: as long as the Lake County Circuit Court case remains active, general contractors and trade contractors face real scheduling uncertainty, and the most effective workforce strategy will rely on flexible, multi-market crews that can shift between Chicago-area projects if Grayslake permitting stalls. Firms that can offer that kind of mobility will have a distinct sourcing advantage at this site. We break down roles, pay bands, and where the talent pool sits in our guide to hiring data center talent in Lake County.

Sources: the Daily Herald, which first reported the permit issuance, the Lake & McHenry County Scanner on the litigation filing, and Patch (Grayslake).