Wisconsin
Data centers in Rock County, Wisconsin
The Census tracks 2 data center projects in Rock County, Wisconsin, with 800 MW of published capacity: 1 proposed, 1 cancelled. 1 moratorium action recorded.
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How many data centers are in Rock County?
The Census tracks 2 major projects here as of Nov 6, 2026: 1 proposed, 1 cancelled. They are in Janesville, Beloit. The largest by published capacity is Viridian Data Center Campus (former GM/JATCO site) (800 MW).
Projects
| Project | Status | Capacity | Developer |
|---|---|---|---|
| Viridian Data Center Campus (former GM/JATCO site) Janesville, Rock County, WI | Cancelled | 800 MW | Viridian Partners (Viridian Acquisitions LLC) |
| Project Cornmaze Beloit, Rock County, WI | Proposed | — | Panattoni |
Moratoriums
| Jurisdiction | Action | Length | What the source says |
|---|---|---|---|
| Town of Beloit Wisconsin · town |
Vote to draft a pause Aug 17, 2026 |
12 months | Supervisors voted 4-0 on a resolution starting the process for a 12-month moratorium; a public hearing and an ordinance were still to come. Beloit Daily NewsSource excerpt“calling for a 12-month moratorium on data center projects” |
Recent changes
| Date | What changed | Project |
|---|---|---|
| Aug 17, 2026 | Town of Beloit board votes 4-0 on a resolution calling for a 12-month data center moratorium; a public hearing and an ordinance are still required Beloit Daily News | Project Cornmaze |
| Jul 31, 2026 | Town of Beloit supervisors reject the cost reimbursement agreement with Panattoni and begin the process toward a 12-month data center moratorium, two days after the Town of Turtle took similar steps Beloit Daily News | Project Cornmaze |
| Jun 22, 2026 | Panattoni holds an invite-only gathering on the project WIFR / Rockford News First | Project Cornmaze |
| Jun 2026 | Panattoni says the Town of Turtle board postponed a cost reimbursement agreement that had been set for its June 9 meeting DCD | Project Cornmaze |
| Jun 2026 | City Council votes not to extend the letter of intent with Viridian WMTV 15 News | Viridian Data Center Campus (former GM/JATCO site) |
| May 2026 | Panattoni informs local government it is taking over the project DCD | Project Cornmaze |
| Mar 5, 2026 | Pre-development agreement for Project Cornmaze becomes public DCD | Project Cornmaze |
| Feb 9, 2026 | City Council places a citizen initiative requiring voter approval for projects over $450 million at the GM/JATCO site on the Nov. 3, 2026 ballot Ballotpedia News | Viridian Data Center Campus (former GM/JATCO site) |
| Nov 2025 | Janesville City Council approves a letter of intent with Viridian 5-2 WPR | Viridian Data Center Campus (former GM/JATCO site) |
| Jul 15, 2025 | Town of Beloit signs pre-development agreement with Cambrin LLC WPR | Project Cornmaze |
| Jun 2024 | City of Janesville begins discussions with Viridian Partners on redeveloping the former GM site The Gazette (gazettextra.com) | Viridian Data Center Campus (former GM/JATCO site) |
Rock County data centers: common questions
How many data centers are in Rock County, Wisconsin?
The Census tracks 2 major data center projects in Rock County as of Nov 6, 2026: 1 proposed, 1 cancelled. That covers major sourced projects, not every smaller colocation or enterprise facility.
What is the biggest data center project in Rock County?
By published planned capacity, Viridian Data Center Campus (former GM/JATCO site) in Janesville, at 800 MW. Its status is cancelled.
Is there a data center moratorium in Rock County?
Town of Beloit voted to direct staff to draft a pause on data center applications (Aug 17, 2026), 12 months. Details and sources are in the moratorium tracker.
This page collects the county-level record: every tracked project, moratorium and local rule we can source for Rock County. See all Wisconsin projects or look up projects near your ZIP code.
Cite this page
Last updated Nov 6, 2026. Figures may change as records are updated — include the date you retrieved them.
| APA | Data Center Census. (2026). Data centers in Rock County, Wisconsin. Retrieved from https://datacentercensus.com/us/wisconsin/rock-county |
|---|---|
| MLA | “Data centers in Rock County, Wisconsin.” Data Center Census, Nov 6, 2026, https://datacentercensus.com/us/wisconsin/rock-county. |
| Link | https://datacentercensus.com/us/wisconsin/rock-county |
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