STACK Chicago CHI01 (Elk Grove, formerly T5 Chicago II) data center, Elk Grove Village, Illinois

STACK Infrastructure's CHI01 data center stands at 1441 Touhy Avenue in Elk Grove Village, Cook County, Illinois, in the village's business park near O'Hare, and STACK counts it among its operating campuses. The building used to belong to T5 Data Centers, which bought it in 2016 before T5 combined facilities with IPI Partners in 2019 to form STACK.

In March 2025 STACK announced a second Elk Grove campus, CHI02, a two-story data center on 18 acres about a mile away with closed-loop cooling; Mayor Craig Johnson welcomed it as "the kind of investment that drives our local economic growth while rejuvenating valuable industrial real estate." Elk Grove Village has 20 operating data centers and 19 more in the pipeline, the second-highest concentration in the country after Northern Virginia.

In May 2026 more than 500 people filled a village town hall on data centers, where Johnson argued that claims about water and electricity use were unfounded and said generator noise is shielded from homes. Residents asked the village to ban gas-powered generators at data centers and to cap how many can be built, and questioned the power demands of AI data centers, the incentives offered to companies and how few jobs data centers create; the village says data center taxes paid for $400 credits on residents' water bills.